U.S. patent application number 12/628198 was filed with the patent office on 2010-03-25 for health monitor.
This patent application is currently assigned to Abbott Diabetes Care Inc.. Invention is credited to Daniel Bernstein, Jean-Pierre Cole, Martin J. Fennell, Namvar Kiaie, Michael Love, Steve Scott, Mark K. Sloan, Jared Watkin.
Application Number | 20100076291 12/628198 |
Document ID | / |
Family ID | 40137215 |
Filed Date | 2010-03-25 |
United States Patent
Application |
20100076291 |
Kind Code |
A1 |
Bernstein; Daniel ; et
al. |
March 25, 2010 |
Health Monitor
Abstract
Methods and devices to detect analyte in body fluid are
provided. Embodiments include enhanced analyte monitoring devices
and systems.
Inventors: |
Bernstein; Daniel; (El
Granada, CA) ; Watkin; Jared; (Danville, CA) ;
Fennell; Martin J.; (Concord, CA) ; Sloan; Mark
K.; (Redwood City, CA) ; Love; Michael;
(Pleasanton, CA) ; Kiaie; Namvar; (Danville,
CA) ; Cole; Jean-Pierre; (Tracy, CA) ; Scott;
Steve; (Pleasanton, CA) |
Correspondence
Address: |
JACKSON & CO., LLP
6114 LA SALLE AVENUE, #507
OAKLAND
CA
94611-2802
US
|
Assignee: |
Abbott Diabetes Care Inc.
Alameda
CA
|
Family ID: |
40137215 |
Appl. No.: |
12/628198 |
Filed: |
November 30, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12143734 |
Jun 20, 2008 |
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12628198 |
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60945581 |
Jun 21, 2007 |
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Current U.S.
Class: |
600/365 |
Current CPC
Class: |
A61B 5/14865 20130101;
A61B 2560/0276 20130101; A61B 2560/0443 20130101; A61B 2560/0223
20130101; A61B 5/0017 20130101; A61B 5/1468 20130101; A61B 5/4839
20130101; A61B 5/14532 20130101; A61B 5/002 20130101; A61B 2560/045
20130101; A61B 2560/0475 20130101; A61B 2560/0456 20130101; A61B
5/1495 20130101 |
Class at
Publication: |
600/365 |
International
Class: |
A61B 5/145 20060101
A61B005/145 |
Claims
1. A health monitoring system, comprising: a monitoring device,
comprising: an analyte sensor to monitor an analyte level; and a
data transfer module in signal communication with the analyte
sensor and receiving one or more signals related to the monitored
analyte level from the analyte sensor, the data transfer module
transmitting data related to the monitored analyte level upon
receiving a request, the data transfer module including a memory to
store the data related to the monitored analyte level; and a
glucose meter device, comprising: a housing; a data processing unit
coupled to the housing, the data processing unit generating the
request for the data related to the monitored analyte level and
processing the data received in response to the request; a
communication unit operatively coupled to the data processing unit
to transmit the generated request and to receive the data related
to the monitored analyte level in response to the request; and a
memory operatively coupled to the data processing unit and
configured to store the received data associated with the monitored
analyte level or the processed data related to the monitored
analyte level or both.
2. The system of claim 1 wherein the data transfer module transmits
the stored data related to the monitored analyte level only upon
receiving the generated request.
3. The system of claim 1 wherein upon receiving the request, the
data transfer module transmits data stored in the memory related to
the monitored analyte level, or data related to a substantially
real time analyte level or both the data stored in the memory
related to the monitored analyte level and the data related to the
substantially real time analyte level.
4. The system of claim 1 wherein the analyte sensor is a glucose
sensor.
5. The system of claim 1 wherein the data transfer module transmits
a unique identifier with the transmitted data related to the
monitored analyte level.
6. The system of claim 5 wherein the data transfer module is
synchronized with the glucose meter device based at least in part
on the transmitted unique identifier.
7. The system of claim 1 wherein the data related to the monitored
analyte level is transmitted based on one or more of a wireless
communication protocol or a wired connection.
8. The system of claim 7 wherein the wireless communication
protocol includes a radio frequency (RF) communication protocol,
optical communication protocol, Bluetooth communication protocol,
or Zigbee communication protocol.
9. The system of claim 7 wherein the wired connection includes a
universal serial bus (USB) connection or a cable connection.
10. The system of claim 1 wherein the memory of the data transfer
module buffers the data related to the monitored analyte level.
11. The system of claim 10 wherein the data transfer module
includes a control unit to transmit the buffered data related to
the monitored analyte level only upon receiving the request.
12. The system of claim 1 wherein the data transfer module operates
in one or more of a first data transmission mode, a second data
transmission mode, or a third data transmission mode.
13. The system of claim 12 wherein the first data transmission mode
includes transmitting the data related to the monitored analyte
level in response to the request when a new sensor data is
available.
14. The system of claim 12 wherein the second data transmission
mode includes transmitting the data related to the monitored
analyte level when a new sensor data is available and storing the
data related to the monitored analyte level for retransmission.
15. The system of claim 12 wherein the third transmission mode
includes storing the data related to the monitored analyte level
and transmitting the stored data related to the monitored analyte
level in response to the request.
16. The system of claim 1 wherein the data transfer module is
configured to perform one or more of a prospective analysis or a
retrospective analysis on the monitored analyte level.
18. The system of claim 1 wherein the analyte sensor is configured
to require no system calibration.
19. The system of claim 1 wherein the analyte sensor is configured
to require no user calibration.
20. The system of claim 1 wherein the analyte sensor is configured
for automatic calibration.
Description
RELATED APPLICATION
[0001] The present application is a continuation of U.S. patent
application no. 12/143,734 filed Jun. 20, 2008, entitled "Health
Monitor", which claims priority to U.S. provisional application No.
60/945,581 filed Jun. 21, 2007, entitled "Health Monitor" and
assigned to the assignee of the present application, Abbott
Diabetes Care Inc., the disclosure of which is incorporated herein
by reference for all purposes.
BACKGROUND
[0002] The detection of the level of analytes, such as glucose,
lactate, oxygen, and the like, in certain individuals is vitally
important to their health. For example, the monitoring of glucose
is particularly important to individuals with diabetes. Diabetics
may need to monitor glucose levels to determine when insulin is
needed to reduce glucose levels in their bodies or when additional
glucose is needed to raise the level of glucose in their
bodies.
[0003] Accordingly, of interest are devices, system and methods
that allow a user to test for one or more analytes.
SUMMARY
[0004] Embodiments include enhanced in vitro analyte meters and
systems which are enhanced with in vivo continuous analyte
monitoring functionality. The descriptions herein describe in vitro
analyte glucose meters primarily as in vitro blood glucose ("BG")
meters and in vivo continuous analyte system primarily as in vivo
continuous glucose ("CG") monitoring devices and systems, for
convenience only. Such descriptions are in no way intended to limit
the scope of the disclosure in any way.
[0005] Accordingly, BG meters and systems having high levels of
functionality are provided. Each BG or CG system may accept and
process data from its own respective system and/or from another
system, e.g., a BG system may accept and process CG system data, or
vice versa. Embodiments enable CG data to be provided to a user by
way of a BG meter.
[0006] Embodiments may be useful to users who may require
conventional blood glucose BG data most of the time, but who may
have a periodic need for CG data. One way this problem has been
addressed in the past is to provide the user with both a BG meter
and a CG system. However, this has the disadvantage of cost because
a CG system may be more expensive than a BG meter, and increased
training as the user must learn how to use two meters a BG meter
for normal use and a CG meter for those times when CG data is
required.
[0007] Embodiments herein may be appropriate for Type I and Type II
diabetics, other patients experiencing diabetic conditions, or
patients in post surgery recovery period.
[0008] Also provided are devices, methods and kits.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 shows a block diagram of an embodiment of a data
monitoring and management system according to the present
disclosure;
[0010] FIG. 2 shows a block diagram of an embodiment of the
transmitter unit of the data monitoring and management system of
FIG. 1;
[0011] FIG. 3 shows a block diagram of an embodiment of the
receiver/monitor unit of the data monitoring and management system
of FIG. 1;
[0012] FIG. 4 shows a schematic diagram of an embodiment of an
analyte sensor according to the present disclosure;
[0013] FIGS. 5A-5B show a perspective view and a cross sectional
view, respectively of another embodiment an analyte sensor;
[0014] FIG. 6 shows an exemplary embodiment of a system that
includes a CG Data Logger (for example, including a data storage
device or memory) and an enhanced BG meter, in which the CG Data
Logger is capable of transferring CG data obtained by a CG analyte
sensor positioned at least partially beneath a skin surface of a
user to the enhanced BG meter;
[0015] FIG. 7 shows an exemplary embodiment of a Modular System
that includes a CG unit having a transmitter, data transfer module
and enhanced BG meter, in which the CG unit is capable of
wirelessly transferring data obtained by a CG analyte sensor
positioned at least partially beneath a skin surface of a user to
the enhanced BG meter by way of the data transfer module;
[0016] FIG. 8 shows an exemplary embodiment of an integrated system
that includes an enhanced BG meter and a CG unit having a
transmitter, in which the CG unit is capable of transferring CG
data obtained by a CG analyte sensor positioned at least partially
beneath a skin surface of a user to the enhanced BG meter in real
time;
[0017] FIG. 9 shows an exemplary embodiment of a system which
includes a BG meter and a docking unit, herein shown configured as
a belt holster;
[0018] FIGS. 10A-10C show exemplary embodiments of glucose test
strips that may be used with the enhanced systems described herein;
and
[0019] FIGS. 11A-11C show exemplary BG meters.
DETAILED DESCRIPTION
[0020] Before the present disclosure is described, it is to be
understood that this disclosure is not limited to particular
embodiments described, as such may, of course, vary. It is also to
be understood that the terminology used herein is for the purpose
of describing particular embodiments only, and is not intended to
be limiting, since the scope of the present disclosure will be
limited only by the appended claims.
[0021] Where a range of values is provided, it is understood that
each intervening value, to the tenth of the unit of the lower limit
unless the context clearly dictates otherwise, between the upper
and lower limit of that range and any other stated or intervening
value in that stated range, is encompassed within the disclosure.
The upper and lower limits of these smaller ranges may
independently be included in the smaller ranges is also encompassed
within the disclosure, subject to any specifically excluded limit
in the stated range. Where the stated range includes one or both of
the limits, ranges excluding either or both of those included
limits are also included in the disclosure.
[0022] It must be noted that as used herein and in the appended
claims, the singular forms "a", "an", and "the" include plural
referents unless the context clearly dictates otherwise.
[0023] As will be apparent to those of skill in the art upon
reading this disclosure, each of the individual embodiments
described and illustrated herein has discrete components and
features which may be readily separated from or combined with the
features of any of the other several embodiments without departing
from the scope or spirit of the present disclosure.
[0024] The figures shown herein are not necessarily drawn to scale,
with some components and features being exaggerated for
clarity.
[0025] Embodiments include devices which allow diabetic patients to
measure the blood (or other bodily fluid) glucose levels, e.g.,
hand-held electronic meters (blood glucose meters), e.g., such as
Freestyle.RTM. or Precision.RTM. blood glucose monitoring systems
available from Abbott Diabetes Care, Inc., of Alameda, Calif. (and
the like) which receives blood samples via enzyme-based test
strips. Typically, a user inserts a test strip into a meter and
lances a finger or alternate body site to obtain a blood sample.
The drawn sample is applied to the test strip and the meter reads
the strip and determines analyte concentration, which is then
conveyed to the user. For example, the blood glucose meter converts
a current generated by the enzymatic reaction in the test strip to
a corresponding blood glucose value which is displayed or otherwise
provided to the patient to show the level of glucose at the time of
testing.
[0026] Such periodic discrete glucose testing helps diabetic
patients to take any necessary corrective actions to better manage
diabetic conditions.
[0027] Test strips may be adapted to measure the concentration of
an analyte in any volume of sample, including but not limited to
small volumes of sample, e.g., about 1 microliter or less sample,
for example about 0.5 microliters or less, for example about 0.3
microliters or less, for example about 0.1 microliters or less. In
some embodiments, the volume of sample may be as low as about 0.05
microliters or as low as about 0.03 microliters. Strips may be
configures so that an accurate analyte measurement may be obtained
using a volume of sample that wholly or partially fills a sample
chamber of a strip. In certain embodiments, a test may only start
when sufficient sample has been applied to a strip, e.g., as
detected by a detector such as an electrode. A system may be
programmed to allow re-application of additional sample if
insufficient sample is firstly applied, e.g., the time to reapply
sample may range from about 10 seconds to about 2 minutes, e.g.,
from about 30 seconds to about 60 seconds.
[0028] Strips may be side fill, front fill, top fill or corner
fill, or any combination thereof. Test strips may be
calibration-free, e.g., minimal input (if any) is required of a
user to calibrate. In certain embodiments, no calibration test
strips may be employed. In such embodiments, the user need not take
any action for calibration, i.e., calibration is invisible to a
user.
[0029] As noted above, strips are used with meters. In certain
embodiments, meters may be integrated meters, i.e., a device which
has at least one strip and at least a second element, such as a
meter and/or a skin piercing element such as a lancet or the like,
in the device. In some embodiments, a strip may be integrated with
both a meter and a lancet, e.g., in a single housing. Having
multiple elements together in one device reduces the number of
devices needed to obtain an analyte level and facilitates the
sampling process. For example, embodiments may include a housing
that includes one or more analyte test strips, a skin piercing
element and a processor for determining the concentration of an
analyte in a sample applied to the strip. A plurality of strips may
be retained in a magazine in the housing interior and, upon
actuation by a user, a single strip may be dispensed from the
magazine so that at least a portion extends out of the housing for
use.
[0030] Test strips may be short test time test strips. For example,
test times may range from about 1 second to about 20 seconds, e.g.,
from about 3 seconds to about 10 seconds, e.g., from about 3
seconds to about 7 seconds, e.g., about 5 seconds or about 3
seconds.
[0031] Exemplary meters and test strips and using the same are
shown in FIGS. 10A-10C and 11A-11C.
[0032] Embodiments include analyte monitoring devices and systems
that include an analyte sensor--at least a portion of which is
positionable beneath the skin of the user--for the in vivo
detection, of at least one analyte, such as glucose, lactate, and
the like, in a body fluid. Such in vivo sensors are generally
referred to herein as in vivo sensors/systems and/or continuous
sensors/systems, where such are used interchangeably unless
indicated otherwise. Embodiments include wholly implantable analyte
sensors and analyte sensors in which only a portion of the sensor
is positioned under the skin and a portion of the sensor resides
above the skin, e.g., for contact to a transmitter, receiver,
transceiver, processor, etc. The sensor may be, for example,
subcutaneously positionable in a patient for the continuous or
periodic monitoring of a level of an analyte in a patient's
interstitial fluid. For the purposes of this description,
continuous monitoring and periodic monitoring will be used
interchangeably, unless noted otherwise. The sensor response may be
correlated and/or converted to analyte levels in blood or other
fluids. In certain embodiments, an analyte sensor may be positioned
in contact with interstitial fluid to detect the level of glucose,
which detected glucose may be used to infer the glucose level in
the patient's bloodstream. Analyte sensors may be insertable into a
vein, artery, or other portion of the body containing fluid.
Embodiments of the analyte sensors of the subject disclosure may be
configured for monitoring the level of the analyte over a time
period which may range from minutes, hours, days, weeks, or longer.
Analyte sensors that do not require contact with bodily fluid are
also contemplated.
[0033] Of interest are analyte sensors, such as glucose sensors,
that are capable of in vivo detection of an analyte for about one
hour or more, e.g., about a few hours or more, e.g., about a few
days of more, e.g., about three or more days, e.g., about five days
or more, e.g., about seven days or more, e.g., about several weeks
or at least one month. Future analyte levels may be predicted based
on information obtained, e.g., the current analyte level at time
t.sub.0, the rate of change of the analyte, etc. Predictive alarms
may notify the user of a predicted analyte levels that may be of
concern in advance of the user's analyte level reaching the future
level. This provides the user an opportunity to take corrective
action.
[0034] FIG. 1 shows a data monitoring and management system such
as, for example, an analyte (e.g., glucose) monitoring system 100
in accordance with certain embodiments. Embodiments of the subject
disclosure are further described primarily with respect to glucose
monitoring devices and systems, and methods of glucose detection,
for convenience only and such description is in no way intended to
limit the scope of the disclosure. It is to be understood that the
analyte monitoring system may be configured to monitor a variety of
analytes at the same time or at different times.
[0035] Analytes that may be monitored include, but are not limited
to, acetyl choline, amylase, bilirubin, cholesterol, chorionic
gonadotropin, creatine kinase (e.g., CK-MB), creatine, creatinine,
DNA, fructosamine, glucose, glutamine, growth hormones, hormones,
ketone bodies, lactate, peroxide, prostate-specific antigen,
prothrombin, RNA, thyroid stimulating hormone, and troponin. The
concentration of drugs, such as, for example, antibiotics (e.g.,
gentamicin, vancomycin, and the like), digitoxin, digoxin, drugs of
abuse, theophylline, and warfarin, may also be monitored. In those
embodiments that monitor more than one analyte, the analytes may be
monitored at the same or different times.
[0036] The analyte monitoring system 100 includes a sensor 101, a
data processing unit 102 connectable to the sensor 101, and a
primary receiver unit 104 which is configured to communicate with
the data processing unit 102 via a communication link 103. In
certain embodiments, the primary receiver unit 104 may be further
configured to transmit data to a data processing terminal 105 to
evaluate or otherwise process or format data received by the
primary receiver unit 104. The data processing terminal 105 may be
configured to receive data directly from the data processing unit
102 via a communication link which may optionally be configured for
bi-directional communication. Further, the data processing unit 102
may include a transmitter or a transceiver to transmit and/or
receive data to and/or from the primary receiver unit 104 and/or
the data processing terminal 105 and/or optionally the secondary
receiver unit 106.
[0037] Also shown in FIG. 1 is an optional secondary receiver unit
106 which is operatively coupled to the communication link and
configured to receive data transmitted from the data processing
unit 102. The secondary receiver unit 106 may be configured to
communicate with the primary receiver unit 104, as well as the data
processing terminal 105. The secondary receiver unit 106 may be
configured for bi-directional wireless communication with each of
the primary receiver unit 104 and the data processing terminal 105.
As discussed in further detail below, in certain embodiments the
secondary receiver unit 106 may be a de-featured receiver as
compared to the primary receiver, i.e., the secondary receiver may
include a limited or minimal number of functions and features as
compared with the primary receiver unit 104. As such, the secondary
receiver unit 106 may include a smaller (in one or more, including
all, dimensions), compact housing or embodied in a device such as a
wrist watch, arm band, etc., for example. Alternatively, the
secondary receiver unit 106 may be configured with the same or
substantially similar functions and features as the primary
receiver unit 104. The secondary receiver unit 106 may include a
docking portion to be mated with a docking cradle unit for
placement by, e.g., the bedside for night time monitoring, and/or a
bi-directional communication device. A docking cradle may recharge
a powers supply.
[0038] Only one sensor 101, data processing unit or control unit
102 and data processing terminal 105 are shown in the embodiment of
the analyte monitoring system 100 illustrated in FIG. 1. However,
it will be appreciated by one of ordinary skill in the art that the
analyte monitoring system 100 may include more than one sensor 101
and/or more than one data processing unit 102, and/or more than one
data processing terminal 105. Multiple sensors may be positioned in
a patient for analyte monitoring at the same or different times. In
certain embodiments, analyte information obtained by a first
positioned sensor may be employed as a comparison to analyte
information obtained by a second sensor. This may be useful to
confirm or validate analyte information obtained from one or both
of the sensors. Such redundancy may be useful if analyte
information is contemplated in critical therapy-related decisions.
In certain embodiments, a first sensor may be used to calibrate a
second sensor.
[0039] The analyte monitoring system 100 may be a continuous
monitoring system, or semi-continuous, or a discrete monitoring
system. In a multi-component environment, each component may be
configured to be uniquely identified by one or more of the other
components in the system so that communication conflict may be
readily resolved between the various components within the analyte
monitoring system 100. For example, unique IDs, communication
channels, and the like, may be used.
[0040] In certain embodiments, the sensor 101 is physically
positioned in or on the body of a user whose analyte level is being
monitored. The sensor 101 may be configured to at least
periodically sample the analyte level of the user and convert the
sampled analyte level into a corresponding signal for transmission
by the data processing unit 102. The data processing unit 102 is
coupleable to the sensor 101 so that both devices are positioned in
or on the user's body, with at least a portion of the analyte
sensor 101 positioned transcutaneously. The data processing unit
may include a fixation element such as adhesive or the like to
secure it to the user's body. A mount (not shown) attachable to the
user and mateable with the unit 102 may be used. For example, a
mount may include an adhesive surface. The data processing unit 102
performs data processing functions, where such functions may
include but are not limited to, amplification, filtering and
encoding of data signals, each of which corresponds to a sampled
analyte level of the user, for transmission to the primary receiver
unit 104 via the communication link 103. In one embodiment, the
sensor 101 or the data processing unit 102 or a combined
sensor/data processing unit may be wholly implantable under the
skin layer of the user.
[0041] In certain embodiments, the primary receiver unit 104 may
include an analog interface section including an RF receiver and an
antenna that is configured to communicate with the data processing
unit 102 via the communication link 103, and a data processing
section for processing the received data from the data processing
unit 102 such as data decoding, error detection and correction,
data clock generation, data bit recovery, etc., or any combination
thereof.
[0042] In operation, the primary receiver unit 104 in certain
embodiments is configured to synchronize with the data processing
unit 102 to uniquely identify the data processing unit 102, based
on, for example, an identification information of the data
processing unit 102, and thereafter, to periodically receive
signals transmitted from the data processing unit 102 associated
with the monitored analyte levels detected by the sensor 101.
[0043] Referring again to FIG. 1, the data processing terminal 105
may include a personal computer, a portable computer such as a
laptop or a handheld device (e.g., personal digital assistants
(PDAs), telephone such as a cellular phone (e.g., a multimedia and
Internet-enabled mobile phone such as an iPhone or similar phone),
mp3 player, pager, and the like), drug delivery device, each of
which may be configured for data communication with the receiver
via a wired or a wireless connection. Additionally, the data
processing terminal 105 may further be connected to a data network
(not shown) for storing, retrieving, updating, and/or analyzing
data corresponding to the detected analyte level of the user.
[0044] The data processing terminal 105 may include an infusion
device such as an insulin infusion pump or the like, which may be
configured to administer insulin to patients, and which may be
configured to communicate with the primary receiver unit 104 for
receiving, among others, the measured analyte level. Alternatively,
the primary receiver unit 104 may be configured to integrate an
infusion device therein so that the primary receiver unit 104 is
configured to administer insulin (or other appropriate drug)
therapy to patients, for example, for administering and modifying
basal profiles, as well as for determining appropriate boluses for
administration based on, among others, the detected analyte levels
received from the data processing unit 102. An infusion device may
be an external device or an internal device (wholly implantable in
a user).
[0045] In certain embodiments, the data processing terminal 105,
which may include an insulin pump, may be configured to receive the
analyte signals from the data processing unit 102, and thus,
incorporate the functions of the primary receiver unit 104
including data processing for managing the patient's insulin
therapy and analyte monitoring. In certain embodiments, the
communication link 103 as well as one or more of the other
communication interfaces shown in FIG. 1, may use one or more of:
an RF communication protocol, an infrared communication protocol, a
Bluetooth enabled communication protocol, an 802.11x wireless
communication protocol, or an equivalent wireless communication
protocol which would allow secure, wireless communication of
several units (for example, per HIPPA requirements), while avoiding
potential data collision and interference.
[0046] FIG. 2 shows a block diagram of an embodiment of a data
processing unit of the data monitoring and detection system shown
in FIG. 1. User input and/or interface components may be included
or a data processing unit may be free of user input and/or
interface components. In certain embodiments, one or more
application-specific integrated circuits (ASIC) may be used to
implement one or more functions or routines associated with the
operations of the data processing unit (and/or receiver unit) using
for example one or more state machines and buffers. The processor
shown in FIG. 2 may be equipped with sufficient memory to store the
data of interest (such as analyte data) for extended periods of
time ranging from one to several samples to the number of samples
obtained for an entire wear period of several days to weeks. In one
aspect, the memory may be included as part of the processor 204. In
another embodiment, a separate memory unit such as a memory chip,
random access memory (RAM) or any other storage device for storing
for subsequent retrieval data. For example, as shown, the data
processing unit may include a storage unit 215 operative coupled to
the processor 204, and configured to store the analyte data
received, for example, from the sensor 101 (FIG. 1). In one aspect,
the storage unit 215 may be configured to store a large volume of
data received over a predetermined time period from the sensor,
and, the processor 204 may be configured to, for example, transmit
the stored analyte sensor data in a batch mode, for example, after
collecting and storing over a defined time period in a single or
multiple data transmission. In another aspect, the processor 204
may be configured such that the received analyte sensor data is e
transmitted in real time, when received from the analyte
sensor.
[0047] Also, the processor 204 may be configured to anticipate or
wait for a receipt confirmation signal from the recipient of the
data transmission (for example, the receiver unit 104 FIG. 1),
where when the signal receipt confirmation signal is not received,
the processor 204 of the data processing unit 102 may be configured
to retrieve the stored analyte sensor data and retransmit it to the
receiver unit 104, for example.
[0048] As can be seen in the embodiment of FIG. 2, the sensor unit
101 (FIG. 1) includes four contacts, three of which are
electrodes--work electrode (W) 210, reference electrode (R) 212,
and counter electrode (C) 213, each operatively coupled to the
analog interface 201 of the data processing unit 102. This
embodiment also shows optional guard contact (G) 211. Fewer or
greater electrodes may be employed. For example, the counter and
reference electrode functions may be served by a single
counter/reference electrode, there may be more than one working
electrode and/or reference electrode and/or counter electrode,
etc.
[0049] FIG. 3 is a block diagram of an embodiment of a
receiver/monitor unit such as the primary receiver unit 104 of the
data monitoring and management system shown in FIG. 1. The primary
receiver unit 104 includes one or more of: a blood glucose test
strip interface 301, an RF receiver 302, an input 303, a
temperature detection section 304, and a clock 305, each of which
is operatively coupled to a processing and storage section 307. The
primary receiver unit 104 also includes a power supply 306
operatively coupled to a power conversion and monitoring section
308. Further, the power conversion and monitoring section 308 is
also coupled to the receiver processor 307. Moreover, also shown
are a receiver serial communication section 309, and an output 310,
each operatively coupled to the processing and storage unit 307.
The receiver may include user input and/or interface components or
may be free of user input and/or interface components.
[0050] In certain embodiments, the test strip interface 301
includes a glucose level testing portion to receive a blood (or
other body fluid sample) glucose test or information related
thereto. For example, the interface may include a test strip port
to receive a glucose test strip. The device may determine the
glucose level of the test strip, and optionally display (or
otherwise notice) the glucose level on the output 310 of the
primary receiver unit 104. Any suitable test strip may be employed,
e.g., test strips that only require a very small amount (e.g., one
microliter or less, e.g., 0.5 microliter or less, e.g., 0.1
microliter or less), of applied sample to the strip in order to
obtain accurate glucose information, e.g. FreeStyle.RTM. blood
glucose test strips from Abbott Diabetes Care Inc. Glucose
information obtained by the in vitro glucose testing device may be
used for a variety of purposes, computations, etc. For example, the
information may be used to calibrate sensor 101, confirm results of
the sensor 101 to increase the confidence thereof (e.g., in
instances in which information obtained by sensor 101 is employed
in therapy related decisions), etc.
[0051] In further embodiments, the data processing unit 102 and/or
the primary receiver unit 104 and/or the secondary receiver unit
105, and/or the data processing terminal/infusion section 105 may
be configured to receive the blood glucose value wirelessly over a
communication link from, for example, a blood glucose meter. In
further embodiments, a user manipulating or using the analyte
monitoring system 100 (FIG. 1) may manually input the blood glucose
value using, for example, a user interface (for example, a
keyboard, keypad, voice commands, and the like) incorporated in the
one or more of the data processing unit 102, the primary receiver
unit 104, secondary receiver unit 105, or the data processing
terminal/infusion section 105.
[0052] Additional detailed description of embodiments of test
strips, blood glucose (BG) meters and continuous monitoring systems
and data management systems that may be employed are provided in
but not limited to: U.S. Pat. No. 6,175,752; U.S. Pat. No.
6,560,471; U.S. Pat. No. 5,262,035; U.S. Pat. No. 6,881,551; U.S.
Pat. No. 6,121,009; U.S. Pat. No. 7,167,818; U.S. Pat. No.
6,270,455; U.S. Pat. No. 6,161,095; U.S. Pat. No. 5,918,603; U.S.
Pat. No. 6,144,837; U.S. Pat. No. 5,601,435; U.S. Pat. No.
5,822,715; U.S. Pat. No. 5,899,855; U.S. Pat. No. 6,071,391; U.S.
Pat. No. 6,120,676; U.S. Pat. No. 6,143,164; U.S. Pat. No.
6,299,757; U.S. Pat. No. 6,338,790; U.S. Pat. No. 6,377,894; U.S.
Pat. No. 6,600,997; U.S. Pat. No. 6,773,671; U.S. Pat. No.
6,514,460; U.S. Pat. No. 6,592,745; U.S. Pat. No. 5,628,890; U.S.
Pat. No. 5,820,551; U.S. Pat. No. 6,736,957; U.S. Pat. No.
4,545,382; U.S. Pat. No. 4,711,245; U.S. Pat. No. 5,509,410; U.S.
Pat. No. 6,540,891; U.S. Pat. No. 6,730,200; U.S. Pat. No.
6,764,581; U.S. Pat. No. 6,299,757; U.S. Pat. No. 6,461,496; U.S.
Pat. No. 6,503,381; U.S. Pat. No. 6,591,125; U.S. Pat. No.
6,616,819; U.S. Pat. No. 6,618,934; U.S. Pat. No. 6,676,816; U.S.
Pat. No. 6,749,740; U.S. Pat. No. 6,893,545; U.S. Pat. No.
6,942,518; U.S. Pat. No. 6,514,718; U.S. patent application Ser.
No. 10/745,878 filed Dec. 26, 2003 entitled "Continuous Glucose
Monitoring System and Methods of Use", and elsewhere, the
disclosures of each which are incorporated herein by reference for
all purposes.
[0053] FIG. 4 schematically shows an embodiment of an analyte
sensor in accordance with the present disclosure. This sensor
embodiment includes electrodes 401, 402 and 403 on a base 404.
Electrodes (and/or other features) may be applied or otherwise
processed using any suitable technology, e.g., chemical vapor
deposition (CVD), physical vapor deposition, sputtering, reactive
sputtering, printing, coating, ablating (e.g., laser ablation),
painting, dip coating, etching, and the like. Materials include but
are not limited to aluminum, carbon (such as graphite), cobalt,
copper, gallium, gold, indium, iridium, iron, lead, magnesium,
mercury (as an amalgam), nickel, niobium, osmium, palladium,
platinum, rhenium, rhodium, selenium, silicon (e.g., doped
polycrystalline silicon), silver, tantalum, tin, titanium,
tungsten, uranium, vanadium, zinc, zirconium, mixtures thereof, and
alloys, oxides, or metallic compounds of these elements.
[0054] The sensor may be wholly implantable in a user or may be
configured so that only a portion is positioned within (internal) a
user and another portion outside (external) a user. For example,
the sensor 400 may include a portion positionable above a surface
of the skin 410, and a portion positioned below the skin. In such
embodiments, the external portion may include contacts (connected
to respective electrodes of the second portion by traces) to
connect to another device also external to the user such as a
transmitter unit. While the embodiment of FIG. 4 shows three
electrodes side-by-side on the same surface of base 404, other
configurations are contemplated, e.g., fewer or greater electrodes,
some or all electrodes on different surfaces of the base or present
on another base, some or all electrodes stacked together,
electrodes of differing materials and dimensions, etc.
[0055] FIG. 5A shows a perspective view of an embodiment of an
electrochemical analyte sensor 500 having a first portion (which in
this embodiment may be characterized as a major portion)
positionable above a surface of the skin 510, and a second portion
(which in this embodiment may be characterized as a minor portion)
that includes an insertion tip 530 positionable below the skin,
e.g., penetrating through the skin and into, e.g., the subcutaneous
space 520, in contact with the user's biofluid such as interstitial
fluid. Contact portions of a working electrode 501, a reference
electrode 502, and a counter electrode 503 are positioned on the
portion of the sensor 500 situated above the skin surface 510.
Working electrode 501, a reference electrode 502, and a counter
electrode 503 are shown at the second section and particularly at
the insertion tip 530. Traces may be provided from the electrode at
the tip to the contact, as shown in FIG. 5A. It is to be understood
that greater or fewer electrodes may be provided on a sensor. For
example, a sensor may include more than one working electrode
and/or the counter and reference electrodes may be a single
counter/reference electrode, etc.
[0056] FIG. 5B shows a cross sectional view of a portion of the
sensor 500 of FIG. 5A.
[0057] The electrodes 510, 502 and 503, of the sensor 500 as well
as the substrate and the dielectric layers are provided in a
layered configuration or construction. For example, as shown in
FIG. 5B, in one aspect, the sensor 500 (such as the sensor unit 101
FIG. 1), includes a substrate layer 504, and a first conducting
layer 501 such as carbon, gold, etc., disposed on at least a
portion of the substrate layer 504, and which may provide the
working electrode. Also shown disposed on at least a portion of the
first conducting layer 501 is a sensing layer 508.
[0058] A first insulation layer such as a first dielectric layer
505 is disposed or layered on at least a portion of the first
conducting layer 501, and further, a second conducting layer 509
may be disposed or stacked on top of at least a portion of the
first insulation layer (or dielectric layer) 505. As shown in FIG.
5B, the second conducting layer 509 may provide the reference
electrode 502, and in one aspect, may include a layer of
silver/silver chloride (Ag/AgCl), gold, etc.
[0059] A second insulation layer 506 such as a dielectric layer in
one embodiment may be disposed or layered on at least a portion of
the second conducting layer 509. Further, a third conducting layer
503 may provide the counter electrode 503. It may be disposed on at
least a portion of the second insulation layer 506. Finally, a
third insulation layer may be disposed or layered on at least a
portion of the third conducting layer 503. In this manner, the
sensor 500 may be layered such that at least a portion of each of
the conducting layers is separated by a respective insulation layer
(for example, a dielectric layer). The embodiment of FIGS. 5A and
5B show the layers having different lengths. Some or all of the
layers may have the same or different lengths and/or widths.
[0060] In certain embodiments, some or all of the electrodes 501,
502, 503 may be provided on the same side of the substrate 504 in
the layered construction as described above, or alternatively, may
be provided in a co-planar manner such that two or more electrodes
may be positioned on the same plane (e.g., side-by side (e.g.,
parallel) or angled relative to each other) on the substrate 504.
For example, co-planar electrodes may include a suitable spacing
there between and/or include dielectric material or insulation
material disposed between the conducting layers/electrodes.
Furthermore, in certain embodiments one or more of the electrodes
501, 502, 503 may be disposed on opposing sides of the substrate
504. In such embodiments, contact pads may be one the same or
different sides of the substrate. For example, an electrode may be
on a first side and its respective contact may be on a second side,
e.g., a trace connecting the electrode and the contact may traverse
through the substrate.
[0061] As noted above, analyte sensors may include an
analyte-responsive enzyme to provide a sensing component or sensing
layer. Some analytes, such as oxygen, can be directly
electrooxidized or electroreduced on a sensor, and more
specifically at least on a working electrode of a sensor. Other
analytes, such as glucose and lactate, require the presence of at
least one electron transfer agent and/or at least one catalyst to
facilitate the electrooxidation or electroreduction of the analyte.
Catalysts may also be used for those analyte, such as oxygen, that
can be directly electrooxidized or electroreduced on the working
electrode. For these analytes, each working electrode includes a
sensing layer (see for example sensing layer 408 of FIG. 5B)
proximate to or on a surface of a working electrode. In many
embodiments, a sensing layer is formed near or on only a small
portion of at least a working electrode.
[0062] The sensing layer includes one or more components designed
to facilitate the electrochemical oxidation or reduction of the
analyte. The sensing layer may include, for example, a catalyst to
catalyze a reaction of the analyte and produce a response at the
working electrode, an electron transfer agent to transfer electrons
between the analyte and the working electrode (or other component),
or both.
[0063] A variety of different sensing layer configurations may be
used. In certain embodiments, the sensing layer is deposited on the
conductive material of a working electrode. The sensing layer may
extend beyond the conductive material of the working electrode. In
some cases, the sensing layer may also extend over other
electrodes, e.g., over the counter electrode and/or reference
electrode (or counter/reference is provided).
[0064] A sensing layer that is in direct contact with the working
electrode may contain an electron transfer agent to transfer
electrons directly or indirectly between the analyte and the
working electrode, and/or a catalyst to facilitate a reaction of
the analyte. For example, a glucose, lactate, or oxygen electrode
may be formed having a sensing layer which contains a catalyst,
such as glucose oxidase, lactate oxidase, or laccase, respectively,
and an electron transfer agent that facilitates the
electrooxidation of the glucose, lactate, or oxygen,
respectively.
[0065] In other embodiments the sensing layer is not deposited
directly on the working electrode. Instead, the sensing layer 64
may be spaced apart from the working electrode, and separated from
the working electrode, e.g., by a separation layer. A separation
layer may include one or more membranes or films or a physical
distance. In addition to separating the working electrode from the
sensing layer the separation layer may also act as a mass transport
limiting layer and/or an interferent eliminating layer and/or a
biocompatible layer.
[0066] In certain embodiments which include more than one working
electrode, one or more of the working electrodes may not have a
corresponding sensing layer, or may have a sensing layer which does
not contain one or more components (e.g., an electron transfer
agent and/or catalyst) needed to electrolyze the analyte. Thus, the
signal at this working electrode may correspond to background
signal which may be removed from the analyte signal obtained from
one or more other working electrodes that are associated with
fully-functional sensing layers by, for example, subtracting the
signal.
[0067] In certain embodiments, the sensing layer includes one or
more electron transfer agents. Electron transfer agents that may be
employed are electroreducible and electrooxidizable ions or
molecules having redox potentials that are a few hundred millivolts
above or below the redox potential of the standard calomel
electrode (SCE). The electron transfer agent may be organic,
organometallic, or inorganic. Examples of organic redox species are
quinones and species that in their oxidized state have quinoid
structures, such as Nile blue and indophenol. Examples of
organometallic redox species are metallocenes such as ferrocene.
Examples of inorganic redox species are hexacyanoferrate (III),
ruthenium hexamine etc.
[0068] In certain embodiments, electron transfer agents have
structures or charges which prevent or substantially reduce the
diffusional loss of the electron transfer agent during the period
of time that the sample is being analyzed. For example, electron
transfer agents include but are not limited to a redox species,
e.g., bound to a polymer which can in turn be disposed on or near
the working electrode. The bond between the redox species and the
polymer may be covalent, coordinative, or ionic. Although any
organic, organometallic or inorganic redox species may be bound to
a polymer and used as an electron transfer agent, in certain
embodiments the redox species is a transition metal compound or
complex, e.g., osmium, ruthenium, iron, and cobalt compounds or
complexes. It will be recognized that many redox species described
for use with a polymeric component may also be used, without a
polymeric component.
[0069] One type of polymeric electron transfer agent contains a
redox species covalently bound in a polymeric composition. An
example of this type of mediator is poly(vinylferrocene). Another
type of electron transfer agent contains an ionically-bound redox
species. This type of mediator may include a charged polymer
coupled to an oppositely charged redox species. Examples of this
type of mediator include a negatively charged polymer coupled to a
positively charged redox species such as an osmium or ruthenium
polypyridyl cation. Another example of an ionically-bound mediator
is a positively charged polymer such as quaternized poly(4-vinyl
pyridine) or poly(1-vinyl imidazole) coupled to a negatively
charged redox species such as ferricyanide or ferrocyanide. In
other embodiments, electron transfer agents include a redox species
coordinatively bound to a polymer. For example, the mediator may be
formed by coordination of an osmium or cobalt 2,2'-bipyridyl
complex to poly(1-vinyl imidazole) or poly(4-vinyl pyridine).
[0070] Suitable electron transfer agents are osmium transition
metal complexes with one or more ligands, each ligand having a
nitrogen-containing heterocycle such as 2,2'-bipyridine,
1,10-phenanthroline, 1-methyl, 2-pyridyl biimidazole, or
derivatives thereof. The electron transfer agents may also have one
or more ligands covalently bound in a polymer, each ligand having
at least one nitrogen-containing heterocycle, such as pyridine,
imidazole, or derivatives thereof. One example of an electron
transfer agent includes (a) a polymer or copolymer having pyridine
or imidazole functional groups and (b) osmium cations complexed
with two ligands, each ligand containing 2,2'-bipyridine,
1,10-phenanthroline, or derivatives thereof, the two ligands not
necessarily being the same. Some derivatives of 2,2'-bipyridine for
complexation with the osmium cation include but are not limited to
4,4'-dimethyl-2,2'-bipyridine and mono-, di-, and
polyalkoxy-2,2'-bipyridines, such as
4,4'-dimethoxy-2,2'-bipyridine. Derivatives of 1,10-phenanthroline
for complexation with the osmium cation include but are not limited
to 4,7-dimethyl-1,10-phenanthroline and mono, di-, and
polyalkoxy-1,10-phenanthrolines, such as
4,7-dimethoxy-1,10-phenanthroline. Polymers for complexation with
the osmium cation include but are not limited to polymers and
copolymers of poly(1-vinyl imidazole) (referred to as "PVI") and
poly(4-vinyl pyridine) (referred to as "PVP"). Suitable copolymer
substituents of poly(1-vinyl imidazole) include acrylonitrile,
acrylamide, and substituted or quaternized N-vinyl imidazole, e.g.,
electron transfer agents with osmium complexed to a polymer or
copolymer of poly(1-vinyl imidazole).
[0071] Embodiments may employ electron transfer agents having a
redox potential ranging from about -200 mV to about +200 mV versus
the standard calomel electrode (SCE). The sensing layer may also
include a catalyst which is capable of catalyzing a reaction of the
analyte. The catalyst may also, in some embodiments, act as an
electron transfer agent. One example of a suitable catalyst is an
enzyme which catalyzes a reaction of the analyte. For example, a
catalyst, such as a glucose oxidase, glucose dehydrogenase (e.g.,
pyrroloquinoline quinone (PQQ), dependent glucose dehydrogenase,
flavine adenine dinucleotide (FAD) dependent glucose dehydrogenase,
or nicotinamide adenine dinucleotide (NAD) dependent glucose
dehydrogenase), may be used when the analyte of interest is
glucose. A lactate oxidase or lactate dehydrogenase may be used
when the analyte of interest is lactate. Laccase may be used when
the analyte of interest is oxygen or when oxygen is generated or
consumed in response to a reaction of the analyte.
[0072] The sensing layer may also include a catalyst which is
capable of catalyzing a reaction of the analyte. The catalyst may
also, in some embodiments, act as an electron transfer agent. One
example of a suitable catalyst is an enzyme which catalyzes a
reaction of the analyte. For example, a catalyst, such as a glucose
oxidase, glucose dehydrogenase (e.g., pyrroloquinoline quinone
(PQQ), dependent glucose dehydrogenase or oligosaccharide
dehydrogenase, flavine adenine dinucleotide (FAD) dependent glucose
dehydrogenase, nicotinamide adenine dinucleotide (NAD) dependent
glucose dehydrogenase), may be used when the analyte of interest is
glucose. A lactate oxidase or lactate dehydrogenase may be used
when the analyte of interest is lactate. Laccase may be used when
the analyte of interest is oxygen or when oxygen is generated or
consumed in response to a reaction of the analyte.
[0073] In certain embodiments, a catalyst may be attached to a
polymer, cross linking the catalyst with another electron transfer
agent (which, as described above, may be polymeric. A second
catalyst may also be used in certain embodiments. This second
catalyst may be used to catalyze a reaction of a product compound
resulting from the catalyzed reaction of the analyte. The second
catalyst may operate with an electron transfer agent to electrolyze
the product compound to generate a signal at the working electrode.
Alternatively, a second catalyst may be provided in an
interferent-eliminating layer to catalyze reactions that remove
interferents.
[0074] Certain embodiments include a Wired Enzyme.TM. sensing layer
(Abbott Diabetes Care, Inc.) that works at a gentle oxidizing
potential, e.g., a potential of about +40 mV. This sensing layer
uses an osmium (Os)-based mediator designed for low potential
operation and is stably anchored in a polymeric layer. Accordingly,
in certain embodiments the sensing element is redox active
component that includes (1) Osmium-based mediator molecules
attached by stable (bidente) ligands anchored to a polymeric
backbone, and (2) glucose oxidase enzyme molecules. These two
constituents are crosslinked together.
[0075] A mass transport limiting layer (not shown), e.g., an
analyte flux modulating layer, may be included with the sensor to
act as a diffusion-limiting barrier to reduce the rate of mass
transport of the analyte, for example, glucose or lactate, into the
region around the working electrodes. The mass transport limiting
layers are useful in limiting the flux of an analyte to a working
electrode in an electrochemical sensor so that the sensor is
linearly responsive over a large range of analyte concentrations
and is easily calibrated. Mass transport limiting layers may
include polymers and may be biocompatible. A mass transport
limiting layer may provide many functions, e.g., biocompatibility
and/or interferent-eliminating, etc.
[0076] In certain embodiments, a mass transport limiting layer is a
membrane composed of crosslinked polymers containing heterocyclic
nitrogen groups, such as polymers of polyvinylpyridine and
polyvinylimidazole. Embodiments also include membranes that are
made of a polyurethane, or polyether urethane, or chemically
related material, or membranes that are made of silicone, and the
like.
[0077] A membrane may be formed by crosslinking in situ a polymer,
modified with a zwitterionic moiety, a non-pyridine copolymer
component, and optionally another moiety that is either hydrophilic
or hydrophobic, and/or has other desirable properties, in an
alcohol-buffer solution. The modified polymer may be made from a
precursor polymer containing heterocyclic nitrogen groups. For
example, a precursor polymer may be polyvinylpyridine or
polyvinylimidazole. Optionally, hydrophilic or hydrophobic
modifiers may be used to "fine-tune" the permeability of the
resulting membrane to an analyte of interest. Optional hydrophilic
modifiers, such as poly(ethylene glycol), hydroxyl or polyhydroxyl
modifiers, may be used to enhance the biocompatibility of the
polymer or the resulting membrane.
[0078] A membrane may be formed in situ by applying an
alcohol-buffer solution of a crosslinker and a modified polymer
over an enzyme-containing sensing layer and allowing the solution
to cure for about one to two days or other appropriate time period.
The crosslinker-polymer solution may be applied to the sensing
layer by placing a droplet or droplets of the solution on the
sensor, by dipping the sensor into the solution, or the like.
Generally, the thickness of the membrane is controlled by the
concentration of the solution, by the number of droplets of the
solution applied, by the number of times the sensor is dipped in
the solution, or by any combination of these factors. A membrane
applied in this manner may have any combination of the following
functions: (1) mass transport limitation, i.e. reduction of the
flux of analyte that can reach the sensing layer, (2)
biocompatibility enhancement, or (3) interferent reduction.
[0079] The description herein is directed primarily to
electrochemical sensors for convenience only and is in no way
intended to limit the scope of the disclosure. Other sensors and
sensor systems are contemplated. Such include, but are not limited
to, optical sensors, colorimetric sensors, potentiometric sensors,
coulometric sensors and sensors that detect hydrogen peroxide to
infer glucose levels, for example. For example, a hydrogen
peroxide-detecting sensor may be constructed in which a sensing
layer includes enzyme such as glucose oxides, glucose
dehydrogenase, or the like, and is positioned proximate to the
working electrode. The sending layer may be covered by a membrane
that is selectively permeable to glucose. Once the glucose passes
through the membrane, it is oxidized by the enzyme and reduced
glucose oxidase can then be oxidized by reacting with molecular
oxygen to produce hydrogen peroxide.
[0080] Certain embodiments include a hydrogen peroxide-detecting
sensor constructed from a sensing layer prepared by crosslinking
two components together, for example: (1) a redox compound such as
a redox polymer containing pendent Os polypyridyl complexes with
oxidation potentials of about +200 mV vs. SCE, and (2) periodate
oxidized horseradish peroxidase (HRP). Such a sensor functions in a
reductive mode; the working electrode is controlled at a potential
negative to that of the Os complex, resulting in mediated reduction
of hydrogen peroxide through the HRP catalyst.
[0081] In another example, a potentiometric sensor can be
constructed as follows. A glucose-sensing layer is constructed by
crosslinking together (1) a redox polymer containing pendent Os
polypyridyl complexes with oxidation potentials from about -200 mV
to +200 mV vs. SCE, and (2) glucose oxidase. This sensor can then
be used in a potentiometric mode, by exposing the sensor to a
glucose containing solution, under conditions of zero current flow,
and allowing the ratio of reduced/oxidized Os to reach an
equilibrium value. The reduced/oxidized Os ratio varies in a
reproducible way with the glucose concentration, and will cause the
electrode's potential to vary in a similar way.
[0082] A sensor may also include an active agent such as an
anticlotting and/or antiglycolytic agent(s) disposed on at least a
portion a sensor that is positioned in a user. An anticlotting
agent may reduce or eliminate the clotting of blood or other body
fluid around the sensor, particularly after insertion of the
sensor. Examples of useful anticlotting agents include heparin and
tissue plasminogen activator (TPA), as well as other known
anticlotting agents. Embodiments may include an antiglycolytic
agent or precursor thereof. Examples of antiglycolytic agents are
glyceraldehyde, fluoride ion, and mannose.
[0083] Sensors may be configured to require no system calibration
or no user calibration. For example, a sensor may be factory
calibrated and need not require further calibrating. In certain
embodiments, calibration may be required, but may be done without
user intervention, i.e., may be automatic. In those embodiments in
which calibration by the user is required, the calibration may be
according to a predetermined schedule or may be dynamic, i.e., the
time for which may be determined by the system on a real-time basis
according to various factors, such as but not limited to glucose
concentration and/or temperature and/or rate of change of glucose,
etc.
[0084] Calibration may be accomplished using an in vitro test strip
(or other reference), e.g., a small sample test strip such as a
test strip that requires less than about 1 microliter of sample
(for example FreeStyle.RTM. blood glucose monitoring test strips
from Abbott Diabetes Care). For example, test strips that require
less than about 1 nanoliter of sample may be used. In certain
embodiments, a sensor may be calibrated using only one sample of
body fluid per calibration event. For example, a user need only
lance a body part one time to obtain sample for a calibration event
(e.g., for a test strip), or may lance more than one time within a
short period of time if an insufficient volume of sample is firstly
obtained. Embodiments include obtaining and using multiple samples
of body fluid for a given calibration event, where glucose values
of each sample are substantially similar. Data obtained from a
given calibration event may be used independently to calibrate or
combined with data obtained from previous calibration events, e.g.,
averaged including weighted averaged, etc., to calibrate. In
certain embodiments, a system need only be calibrated once by a
user, where recalibration of the system is not required.
[0085] Analyte systems may include an optional alarm system that,
e.g., based on information from a processor, warns the patient of a
potentially detrimental condition of the analyte. For example, if
glucose is the analyte, an alarm system may warn a user of
conditions such as hypoglycemia and/or hyperglycemia and/or
impending hypoglycemia, and/or impending hyperglycemia. An alarm
system may be triggered when analyte levels approach, reach or
exceed a threshold value. An alarm system may also, or
alternatively, be activated when the rate of change, or
acceleration of the rate of change, in analyte level increase or
decrease approaches, reaches or exceeds a threshold rate or
acceleration. A system may also include system alarms that notify a
user of system information such as battery condition, calibration,
sensor dislodgment, sensor malfunction, etc. Alarms may be, for
example, auditory and/or visual. Other sensory-stimulating alarm
systems may be used including alarm systems which heat, cool,
vibrate, or produce a mild electrical shock when activated.
[0086] The subject disclosure also includes sensors used in
sensor-based drug delivery systems. The system may provide a drug
to counteract the high or low level of the analyte in response to
the signals from one or more sensors. Alternatively, the system may
monitor the drug concentration to ensure that the drug remains
within a desired therapeutic range. The drug delivery system may
include one or more (e.g., two or more) sensors, a processing unit
such as a transmitter, a receiver/display unit, and a drug
administration system. In some cases, some or all components may be
integrated in a single unit. A sensor-based drug delivery system
may use data from the one or more sensors to provide necessary
input for a control algorithm/mechanism to adjust the
administration of drugs, e.g., automatically or semi-automatically.
As an example, a glucose sensor may be used to control and adjust
the administration of insulin from an external or implanted insulin
pump.
[0087] As discussed above, embodiments of the present disclosure
relate to methods and devices for detecting at least one analyte
such as glucose in body fluid. Embodiments relate to the continuous
and/or automatic in vivo monitoring of the level of one or more
analytes using a continuous analyte monitoring system that includes
an analyte sensor at least a portion of which is to be positioned
beneath a skin surface of a user for a period of time and/or the
discrete monitoring of one or more analytes using an in vitro blood
glucose ("BG") meter in conjunction with an analyte test strip.
Embodiments include combined or combinable devices, systems and
methods and/or transferring data between an in vivo continuous
system and a BG meter system, and include integrated systems.
[0088] Embodiments include "Data Logger" systems which include a
continuous glucose monitoring system (at least an analyte sensor
and control unit (e.g., an on body unit)). The continuous glucose
monitoring ("CG") system may have limited real-time connectivity
with a BG meter. For example, real time connectivity may be limited
to communicating calibration data (e.g., a BG value) to the CG
system or it may have the ability to receive data from the CG
system on demand (as compared to a CG system continuously
broadcasting such data). In one embodiment, the data processing
unit (102) may be an on-body unit that is configured to operate in
several transmission modes. In a first mode, analyte related data
may be transmitted when a new data value (e.g., sensor data) is
available (for example, when received from the analyte sensor).
This mode of operation may result in "lost data" because the data
processing unit 102 does not get confirmation that the data was
successfully received by the receiver unit 104, and in some
embodiments, this data may not be resent.
[0089] In a second transmission mode, data may be transmitted when
the new data is available and the data processing unit 102 may
receive an acknowledgement that such data has been successfully
received, or if the transmission was unsuccessful the data would be
stored ("buffered") for another attempt. This mode reduces the
likelihood of "lost data". In a third mode ("data logging mode"),
the data processing unit 102 may be configured to retain or store
all data (i.e.; not attempt to transmit it when it becomes
available) until the receiver unit (104) requests the data, or
based upon a scheduled data transmission.
[0090] CG data obtained by the CG Data Logger may be processed by
the Data Logger system or by the BG meter and/or by a data
management system ("DMS") which may includes a computer such as a
PC and an optional server. For example, the CoPilot.TM. data
management system from Abbott Diabetes Care, Inc., or the like, may
be employed. In certain embodiments neither the CG system nor the
BG meter are capable of (or have such capability, but the
capability is selectively turned off) supporting continuous real
time CG data communication, thereby substantially reducing power
requirements. Such embodiments are CG Data Loggers in which CG data
resides (i.e., is logged) in a CG control unit (e.g., on-body unit)
until it is retrieved by a BG meter. In other words, a CG Data
Logger buffers the CG data and stores it in memory until the CG
data is downloaded or transferred to the BG meter, e.g., a user
initiates data transfer or transfer may occur at set times. The CG
component logs continuous glucose data, but only gives up this data
to the on-request to a BG meter. Retrieval may be by any suitable
methodology, including but not limited to wireless communication
protocols such as for example RF, optical means (such as an IR
link), Bluetooth, or a direct connection (such as a USB, or the
like), etc. A given BG meter and CG data Logger may be
synchronized, e.g., by one or more unique identifiers, thereby
ensuring preventing inadvertent data exchange between devices.
[0091] FIG. 6 shows an exemplary embodiment of a system that
includes a CG Data Logger and an enhanced BG meter. As shown, the
enhanced BG meter may communicate with the CG Data Logger by a
wired connection and/or by IR or RF. Referring to the Figure, in
one aspect, the CG data logger may be configured to collect and
store monitored analyte data over a predetermined time period (for
example, from a transcutaneous, subcutaneous or implanted analyte
sensor), and transmit the collected and stored analyte data to the
BG meter either continuously in real time, or periodically (for
example, when the CG data logger is in signal communication with
the BG meter (either cabled or wireless), or in a single data
transfer mode, for example, at the end of the predetermined time
period.
[0092] "Modular" embodiments are also provided. Modular systems may
be used in conjunction with the Data Logger system in certain
embodiments. For example, a separable CG data transfer module may
be configured for wireless communication with the CG data logger
and further configured to removably mate with a BG meter to
transfer CG information to the BG meter (see for example FIG. 7).
Modular embodiments include all the necessary hardware (and
software) to support either (or both) continuous (real time) or
"batched" (data logged) CG data collection in a snap-on or
otherwise mateable module that provides CG data to a BG meter.
Alarm functionality may be included in the BG meter, as well as
features to support CG data processing and communication to a user,
e.g., hardware and software to process CG data and/or calibrate CG
data, enhanced user interface to communicate CG information to a
user (in addition to BG information), e.g., may include CG
calibration information, CG trend information, rate of change
indicators to indicate the rate of change of glucose, and the
like.
[0093] Modules may be re-usable by a plurality of users. User
privacy features may be included, e.g., a module may not
permanently store patient data (user data may be automatically
deleted or expunged after a certain time period), data may be
encrypted, password protected, or otherwise provided with one or
more security features that will limit access to only the intended
users. In one aspect, the CG data logger may be configured to
collect and store the monitored analyte data received from an
analyte sensor, and upon establishing data communication with the
BG meter via the data transfer module, communicate the received
analyte data in one or more batch transfer, or continuously in real
time as the analyte sensor data is received from the sensor.
[0094] FIG. 7 shows an exemplary embodiment of a modular system
that includes a CG control unit/transmitter, a mateable module and
an enhanced BG meter. In this embodiment, the CG data
logger/transmitter is shown communicating with the module via RF
where the module is mateably coupled to the BG meter. However,
other suitable data communication approaches may be used including
IR, Bluetooth, Zigbee communication, and the like.
[0095] FIG. 8 shows an integrated or continuous system that
includes an enhanced BG meter and a CG data logger/transmitter,
where the CG data logger is capable of transferring CG data to the
enhanced BG meter directly and in real time, in this embodiment
shown via a wireless protocol. For example, as shown, the enhanced
BG meter may include an RF communication module or chipset that
allows for wireless communication with the CG data logger.
Accordingly, as the continuous analyte sensor data is received by
the CG data logger, the data is substantially contemporaneously
transferred or communicated in real time to the enhanced BG meter
over the RF communication link.
[0096] FIG. 9 shows an exemplary embodiment of a system which
includes a BG meter and a docking unit, herein shown configured as
a belt holster. The BG meter couples to the holster via contacts of
the holster, which correspond to contacts of the BG meter. The BG
meter displays information to the user when electronically coupled
to the holster, i.e., when docked or when in wireless signal
communication with the belt holster (for example, when removed from
the holster). The holster may include some or all functionality of
a primary receiver unit as described below for CG monitoring. For
example, the holster may contain some or all of a FreeStyle
Navigator.RTM. system, e.g., the receiver functionality as
described above. In one aspect, the belt holster may integrate the
CG data logger such that the collected and stored analyte data may
be transferred to the BG meter when docked in the holster (or when
wirelessly synchronized with the belt holster).
[0097] The CG system may be calibrated using the BG meter, e.g.,
when the BG meter is docked. Such as system may be useful in a
variety of instances, e.g., for gestational diabetes,
assessing/diagnosing diabetes, and the like.
[0098] In certain embodiments, the CG system (whether it be modular
or includes a data logger) may be configured with reduced set of
functionalities. For example, it may not include alarms (audible
and/or vibratory and/or visual) and/or glucose rate of change
indicators and/or a visual or user interface display such as a dot
matrix display and/or additional processing power and/or
miniaturized, or it may not include a test strip port. For example,
FIG. 10 illustrates features which may be included in an exemplary
full-featured CG system, and exemplary integrated real time system
and an exemplary Data Logger system.
[0099] In certain embodiments, synchronization between a BG and CG
systems is provided to calibrate the CG sensor using a BG strip
measurement as a reference data point.
[0100] In certain applications, the enhanced BG meters may be used
by those who require more intensive (i.e., continuous) glucose
monitoring, by temporarily or periodically allowing a user's BG
meter to capture CG data without the user having to obtain another
meter. Likewise, the added value to a health care provider ("HCP")
is gained by patients periodically obtaining more detailed blood
glucose information (e.g., prior to regular check up), thus
allowing the HCP to make more informed and suited therapy
adjustments for the patient.
[0101] Various embodiments have extensive applicability. For
example, indwelling or external sensors other than CG sensors may
be included. Data from indwelling or external sensors other than a
CG sensor may be captured by the systems described herein (such as
temperature data, ketone data, and the like). Furthermore,
functions such as weigh management, enhanced data management or
insulin pump control may also be added to a BG meter via the
modular approach to further enhance the meter. In certain
embodiments, a Data Logger includes providing molded electrical
contacts that allow for electrical connections thru the on-body
case without compromising the watertight seal of the case.
[0102] Embodiments herein may provide increased value of a BG meter
to the patient by adding CG functionality to a base BG meter, a low
learning curve such that the user does not need to become familiar
with two different user interfaces (one for the BG unit and another
for the CG system), reduction in cost of the overall system, and
substantial immunity to environments where continuous wireless
communication may be prohibited such as during flight on an
airplane, within hospital or other settings that have sensitive
instrumentation that may interfere with RF or other wireless
signals.
[0103] Accordingly, an analyte monitoring system in one embodiment
includes an analyte sensor for transcutaneous positioning under a
skin layer of a subject, a data processing device operatively
coupled to the analyte sensor, the device comprising: a control
unit, a memory operatively coupled to the control unit and
configured to store a plurality of data associated with the
monitored analyte level received from the sensor, and a
communication unit operatively coupled to the control unit; and a
blood glucose meter configured for signal communication with the
data processing device, where when the control unit of the data
processing device detects a communication link with the blood
glucose meter, the control unit is further configured to retrieve
the stored plurality of data from the memory and to transmit the
retrieved data to the blood glucose meter.
[0104] The blood glucose meter includes a strip port for receiving
a blood glucose test strip.
[0105] The communication unit may be configured to communicate with
the blood glucose meter using one or more of a wired connection, a
USB cable connection, a serial cable connection, an RF
communication protocol, an infrared communication protocol, a
Bluetooth communication protocol, or an 802.11x communication
protocol.
[0106] In one embodiment, data processing device does not include a
user output component, where the user output component includes a
display.
[0107] The control unit may detect the communication link with the
blood glucose meter based on detection of a wired connection to the
meter.
[0108] The retrieved stored plurality of data may correspond to
glucose data of the subject collected over a predetermined time
period.
[0109] The glucose data may be uncalibrated or calibrated.
[0110] The analyte sensor may be a glucose sensor.
[0111] In one aspect, the blood glucose meter may include an output
unit configured to output one or more of the received retrieved
data.
[0112] The output unit may include a display unit operatively
coupled to a housing of the blood glucose meter.
[0113] The output of one or more received data may include a
graphical output, a numerical output, or a text output.
[0114] The blood glucose meter may be configured to calibrate the
received data.
[0115] The blood glucose meter may include a storage unit
configured to store the calibrated data.
[0116] The blood glucose meter may include a storage unit
configured to store the received data.
[0117] In another aspect, the system may include a holster device
for receiving the blood glucose meter, and the data processing unit
may be integrated in the holster device.
[0118] The control unit may be configured to detect the
communication link with the blood glucose meter when the meter is
coupled to the holster.
[0119] The holster device may include a belt clip.
[0120] A method in another embodiment may include transcutaneously
positioning an analyte sensor under a skin layer of a subject,
coupling a data processing device to the analyte sensor, storing in
a memory of the data processing device a plurality of data
associated with the monitored analyte level received from the
sensor, operatively coupling a communication unit to the control
unit, detecting a communication link with the blood glucose meter,
retrieving the stored plurality of data from the memory, and
commanding the communication unit to transmit the retrieved data to
the blood glucose meter.
[0121] The communication link may be established based on one or
more of a wired connection, a USB cable connection, a serial cable
connection, an RF communication protocol, an infrared communication
protocol, a Bluetooth communication protocol, or an 802.11x
communication protocol.
[0122] The method may include displaying on the blood glucose meter
the received analyte data.
[0123] The retrieved data may correspond to glucose data of the
subject collected over a predetermined time period.
[0124] The method may include calibrating the received data.
[0125] In another aspect, the method may include storing the
received data in a memory of the blood glucose meter.
[0126] In still a further aspect, the method may include encrypting
the retrieved data prior to transmitting to the blood glucose
meter.
[0127] Various other modifications and alterations in the structure
and method of operation of the present disclosure will be apparent
to those skilled in the art without departing from the scope and
spirit of the present disclosure. Although the present disclosure
has been described in connection with specific embodiments, it
should be understood that the present disclosure as claimed should
not be unduly limited to such specific embodiments. It is intended
that the following claims define the scope of the present
disclosure and that structures and methods within the scope of
these claims and their equivalents be covered thereby.
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