U.S. patent application number 11/553819 was filed with the patent office on 2007-03-01 for method and system for testing and controlling a custody of a fluid specimen.
This patent application is currently assigned to eScreen, Inc.. Invention is credited to David A. Birkner, John W. Goodin, Murray Lappe, Keith Patten, Bill Whitford.
Application Number | 20070048875 11/553819 |
Document ID | / |
Family ID | 26937042 |
Filed Date | 2007-03-01 |
United States Patent
Application |
20070048875 |
Kind Code |
A1 |
Lappe; Murray ; et
al. |
March 1, 2007 |
METHOD AND SYSTEM FOR TESTING AND CONTROLLING A CUSTODY OF A FLUID
SPECIMEN
Abstract
A system for automatically testing a fluid specimen, e.g.,
urine, to indicate the presence of specified chemical components in
the specimen. The system preferably utilizes an assaying device
comprised of a specimen container having a unique identifier
thereon and a cap which carries at least one test strip. A method
for testing and controlling a custody of the specimen comprises
obtaining a specimen from a donor, wherein the specimen is obtained
at a service site; storing the specimen in the specimen container;
performing a test on the specimen using a reader device in
communication with a computer, wherein the test is performed at the
service site; providing an electronic chain of custody form that
controls a chain of custody procedure for the specimen; and
allowing the donor to sign the electronic chain of custody form at
the service site by signinig an electronic signature pad.
Inventors: |
Lappe; Murray; (Beverly
Hills, CA) ; Birkner; David A.; (Wayland, MA)
; Goodin; John W.; (Coto de Caza, CA) ; Patten;
Keith; (Los Angeles, CA) ; Whitford; Bill;
(Woodland Hills, CA) |
Correspondence
Address: |
HOVEY WILLIAMS LLP
2405 GRAND BLVD., SUITE 400
KANSAS CITY
MO
64108
US
|
Assignee: |
eScreen, Inc.
Overland Park
KS
|
Family ID: |
26937042 |
Appl. No.: |
11/553819 |
Filed: |
October 27, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10954823 |
Sep 30, 2004 |
|
|
|
11553819 |
Oct 27, 2006 |
|
|
|
10779014 |
Feb 13, 2004 |
6964752 |
|
|
10954823 |
Sep 30, 2004 |
|
|
|
10072154 |
Feb 6, 2002 |
6716393 |
|
|
10779014 |
Feb 13, 2004 |
|
|
|
09444926 |
Nov 24, 1999 |
6514461 |
|
|
10072154 |
Feb 6, 2002 |
|
|
|
09245175 |
Feb 5, 1999 |
6342183 |
|
|
09444926 |
Nov 24, 1999 |
|
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|
Current U.S.
Class: |
436/164 |
Current CPC
Class: |
B01L 3/502 20130101;
G16H 40/63 20180101; G01N 35/00871 20130101; G06Q 30/018 20130101;
B01L 2300/0825 20130101; Y10T 436/13 20150115; B01L 2300/021
20130101; B01L 2400/0406 20130101; B01L 2300/046 20130101; G16H
10/40 20180101; B01L 2200/141 20130101; G01N 33/528 20130101; G01N
33/54366 20130101; G01N 33/94 20130101; B01L 2300/042 20130101;
G16H 40/67 20180101; B01L 3/502715 20130101; B01L 2400/0683
20130101; G06K 2019/06253 20130101; B01L 2400/0478 20130101; Y10T
436/25 20150115; B01L 2300/0832 20130101; B01L 3/545 20130101; B01L
2300/069 20130101; B01L 2200/0605 20130101; G06K 19/10 20130101;
B01L 2300/025 20130101; B01L 2300/0663 20130101; G16H 10/60
20180101; Y10T 436/12 20150115; B01L 2300/047 20130101; G06K
9/00154 20130101 |
Class at
Publication: |
436/164 |
International
Class: |
G01N 21/00 20060101
G01N021/00 |
Claims
1. A method of testing a specimen comprising: obtaining a specimen
from a donor; storing the specimen in a specimen container;
performing a test on the specimen; providing an electronic chain of
custody form that controls a chain of custody procedure for the
specimen; and allowing the donor to sign the electronic chain of
custody form by signing an electronic signature pad.
2. The method as claimed in claim 1, wherein the specimen is
obtained at a service site.
3. The method as claimed in claim 2, wherein the test is performed
on the specimen at the service site.
4. The method as claimed in claim 3, wherein the test is performed
using a reader device.
5. A method of testing a specimen comprising: obtaining a specimen
from a donor, wherein the specimen is obtained at a service site;
storing the specimen in a specimen container; performing a test on
the specimen using a reader device in communication with a
computer, wherein the test is performed at the service site;
providing an electronic chain of custody form that controls a chain
of custody procedure for the specimen; and allowing the donor to
sign the electronic chain of custody form at the service site by
signing an electronic signature pad.
6. The method as claimed in claim 5, wherein the reader device is
in communication with an input/output device that enables entering
of information.
7. The method as claimed in claim 6, wherein the input/output
device is in communication with the computer.
8. The method as claimed in claim 6, further comprising the step of
entering donor information into the input/output device.
9. The method as claimed in claim 5, wherein the specimen is
identified by a unique identifier.
10. The method as claimed in claim 9, further comprising the step
of validating the unique identifier.
11. A method comprising: obtaining a specimen from a donor; storing
the specimen in a specimen container on which is located a unique
identifier for positively associating the specimen with the donor;
performing a test on the specimen using a reader device in
communication with a computer; uploading a test result obtained
with the reader device to the computer; providing an electronic
chain of custody form that controls a chain of custody procedure
for the specimen; and having the donor sign the electronic chain of
custody form by signing an electronic signature pad, such that by
signing the chain of custody form, a closely controlled chain of
custody procedure is administered.
12. The method as claimed in claim 11, wherein the computer is a
host computer, and the reader device is in communication with the
host computer via a communications network.
13. The method as claimed in claim 12, wherein the test result is
uploaded to the host computer via the communications network.
14. The method as claimed in claim 12, wherein the reader device is
in communication with an input/output device that enables entering
of information and subsequent uploading of the information to the
host computer.
15. The method as claimed in claim 11, further comprising the step
of entering donor information into the input/output device.
16. The method as claimed in claim 11, further comprising the step
of printing a copy of the electronic chain of custody form.
17. The method as claimed in claim 12, further comprising the step
of uploading the donor information to the host computer.
18. The method as claimed in claim 11, wherein the reader device is
an on-site device operable to perform the test at a service
site.
19. The method as claimed in claim 11, further comprising the step
of validating the unique identifier.
20. A method of testing a specimen comprising: obtaining a specimen
from a donor; storing the specimen in a specimen container having a
unique identifier associated with it; inputting the unique
identifier into a computer; performing a test on the specimen;
providing an electronic chain of custody form that controls a chain
of custody procedure for the specimen; and allowing the donor to
sign the electronic chain of custody form by signing an electronic
signature pad.
21. The method as claimed in claim 20, wherein the specimen is
obtained at a service site.
22. The method as claimed in claim 21, wherein the test is
performed on the specimen at the service site.
23. The method as claimed in claim 22, wherein the test is
performed using a reader device.
24. The method as claimed in claim 23, wherein the reader device
reads the unique identifier associated with the specimen container.
Description
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 10/954,823, filed Sep. 30, 2004, which is a divisional of U.S.
application Ser. No. 10/779,014, filed Feb. 13, 2004, now U.S. Pat.
No. 6,964,752, which is divisional of U.S. application Ser. No.
10/072,154, filed Feb. 6, 2002, now U.S. Pat. No. 6,716,393, which
is a divisional of U.S. application Ser. No. 09/444,926, filed Nov.
25, 1999, now U.S. Pat. No. 6,514,461, which is a
continuation-in-part of U.S. application Ser. No. 09/245,175, filed
Feb. 5, 1999 by Murray Lappe, et al, now U.S. Pat. No. 6,342,183.
U.S. application Ser. No. 11/063,408, filed Feb. 23, 2005; Ser. No.
08/832,957, filed Apr. 4, 1997, now U.S. Pat. No. 5,929,422; Ser.
No. 08/801,041, filed Feb. 14, 1997, now U.S. Pat. No. 5,916,815;
Ser. No. 09/018,487, filed Feb. 4, 1998, now U.S. Pat. No.
6,036,092; and Ser. No. 09/025,559, filed Feb. 18, 1998, now U.S.
Pat. No. 5,902,982, are also related. The disclosures of the
aforementioned applications are herein incorporated by
reference.
BACKGROUND OF THE INVENTION
[0002] This invention relates generally to systems for
automatically testing fluid specimens, e.g. urine or other body
fluids, to detect chemical substances or components therein. Such
systems can be used, for example, to screen employee applicants for
illegal drug use.
[0003] Employee drug testing typically involves an initial
screening test to identify specimens which are negative (i.e., no
drugs present). This test is usually performed with a low cost
immunoassay which is very sensitive to small quantities of drug
metabolites. If a drug metabolite is detected (referred to as
"presumptive positive"), the specimen is then subjected to a
confirmation test which typically utilizes a highly specific test
method, such as a gas chromatography/mass spectrometry (GC/MS), to
identify the specific drug components in the specimen.
[0004] Traditionally, both the screening and confirmation tests
were performed in a common facility, i.e., centralized laboratory.
More recently, systems have been implemented which perform the
screening test at a local service site. They typically employ drug
test kits which follow the tradition of home pregnancy test kits,
i.e., they detect the presence of a specific drug substance(s) in a
urine specimen. Such drug test kits generally identify, in human
readable form, the drug(s) being tested to indicate the presence
(or absence) of that drug. The screening test result with respect
to each particular drug, and to the specimen as a whole, can either
be (1) negative or (2) presumptively positive. If presumptively
positive, then the specimen is generally sent to a remote
laboratory for confirmation testing.
[0005] Inasmuch as disclosure of a presumptive positive test result
can adversely impact an applicant's record and could potentially
lead to litigation and employer liability, it is extremely
important to prevent the inadvertent dissemination of test result
data.
[0006] The aforementioned parent U.S. Pat. No. 6,342,183 describes
an apparatus for locally analyzing a specimen to qualitatively
detect specified chemical components therein. The apparatus
includes an assaying device comprised of a cup for collecting a
fluid specimen and a cap carrying at least one test strip for
visually reacting to one or more specified chemical components in
the specimen. The assaying device is preferably configured to
interact with a reader device capable of reading the reaction of
the test strip to produce an electronic data output.
[0007] More particularly, the apparatus described in application
Ser. No. 09/245,175 includes an open cup defining an interior
volume for accommodating a fluid specimen and an attachable cap
configured for mounting on the cup to seal the interior volume. The
cap carries at least one test strip and an integrated aliquot
delivery mechanism actuatable to wet the test strip with an aliquot
derived from the fluid specimen. The aliquot delivery mechanism
preferably comprises a pump in the form of a plunger for forcing an
aliquot of the fluid specimen onto the test strip. The plunger can
be actuated either manually or automatically, e.g., by a piston
controlled by a compatible reader device. The reader device
preferably includes a microprocessor based controller for actuating
the aliquot delivery mechanism, a camera for producing an image of
the test strip, and a processor for analyzing the image to produce
test result data. The test result data, along with identification
data read from a label carried by the cap, can then be stored or
communicated, e.g., via a modem.
SUMMARY OF THE INVENTION
[0008] The present invention is directed to an improved system and
components thereof for automatically testing a fluid specimen, e.g.
urine, saliva, or other body fluids, to indicate for the presence
of specified chemical components in the specimen.
[0009] A system in accordance with the invention preferably
utilizes an assaying device comprised of a collection cup and a cap
which carries at least one test strip. The device includes an
integrated aliquot delivery mechanism actuatable to wet the test
strip with an aliquot derived from the fluid specimen. The assaying
device is configured to operate in conjunction with an electronic
reader device capable of actuating the aliquot delivery mechanism
and reading the reaction of the test strip.
[0010] A preferred reader device in accordance with the invention
preferably defines a keyed receptacle for accommodating a
complementary shaped cup housing in a particular orientation. The
reader device is comprised of a camera for capturing the image of a
test strip, an actuator for actuating an aliquot delivery
mechanism, and a microprocessor/controller for (1) controlling the
camera and actuator and (2) processing the image.
[0011] In a preferred embodiment of the invention, the reader
device preferably also includes a network connectivity device, e.g.
modem, for enabling communication with a remote host computer.
Although each reader device can operate independently as a
stand-alone device, a preferred system in accordance with the
inventor employs a host computer or server, which communicates, via
a public and/or private network, with a plurality of reader devices
located at separate service sites. Each service site can be
configured to operate as a "thin client" with primary control being
exercised by the host computer via the network. Alternatively,
primary control can be exercised by the reader device at each site
with only high level supervisory control coming from the host
computer.
[0012] A preferred assaying device in accordance with the invention
includes a cap carrying multiple test strips including at least one
component test strip and at least one adulteration test strip. The
cap is either formed of transparent material or is provided with
transparent windows to permit external viewing of the test strips
by the reader device camera. The cap preferably also carries one or
more fiducial marks to facilitate image processing. Further, the
cap preferably also carries machine readable identification
information, e.g., a bar code label, to positively associate the
specimen and test results with the correct individual. Preferably,
the cap does not bear any human readable indicia identifying the
specimen donor or indicating test results.
[0013] A preferred test strip for testing for the presence of
specific chemical components is configured with multiple latent
lines (i.e., markings) which can become visible when the strip is
wetted. The lines preferably include a control or reference line
and multiple drug lines each related to a different chemical
component. If all of the latent lines visually appear within a
certain test interval, e.g., up to eight minutes, after the strip
has been wetted, this will indicate the absence of the specific
chemical components sought. However, if any of those specific
chemical components are present in concentrations above a certain
threshold, their presence will suppress the appearance of one or
more of the drug lines to indicate the presence of such chemical
components.
[0014] A preferred reader device in accordance with the invention
includes a camera located so that the cap is imaged onto the camera
focal plane. The reader device includes a piston motor for driving
a piston against the assaying device to deliver an aliquot to the
test strips. The piston motor also moves a light shield into place
around the cap enabling a light source to illuminate the cap to
enhance the image for the camera.
[0015] A preferred automatic testing system in accordance with the
invention operates as follows: [0016] 1. Fluid deposited into cup
at local site; secure cap in tamper evident fashion; [0017] 2. Site
administrator places assaying device, i.e., cup and cap, into
"keyed" receptacle of local reader and enters ID information;
[0018] 3. Reader alerts host computer via communication network;
[0019] 4. Initiate automatic reader operational sequence: [0020] a.
capture cap image and verify acceptability to proceed [0021] b. run
piston motor to advance piston into assaying device to force fluid
up channels to wet component and adulteration test strips [0022] c.
capture cap image and verify acceptability to proceed [0023] d.
periodically capture additional cap images during development
interval up to about eight minutes [0024] e. analyze captured image
data to determine [0025] 1. test validity [0026] 2. test results
[0027] f. locally display test validity/results and/or communicate
test validity/results to Host computer [0028] g. run piston motor
to withdraw piston from cup [0029] 5. Site administrator removes
cup from reader
[0030] The camera produces a digital representation of the image
incident on the camera focal plane. The processor then analyzes the
digital representation to determine the color of the adulteration
test strip and to locate visible markings on the component test
strip coincident with the reference and drug lines. Image analysis
is preferably performed by initially using fiducial marks on the
cap to first precisely locate the cap image relative to a reference
image. This can, for example, involve rotating, translating, and/or
scaling the cap image. Thereafter, the digital representation of
each test strip is examined to determine the presence (or absence)
of drug lines. This involves first locating the strip reference
line by effectively "drawing" a rectangular region around the
reference line. The region can be considered as a rectangular
matrix of pixels having rows extending across the strip width, each
row being comprised of multiple column positions. For each row, the
image is examined to determine whether the pixel at each column
position exceeds a threshold. The sum of pixels exceeding the
threshold is determined for each row. These row sums produce a
graph whose x axis is related to the height (i.e., number of rows)
of the region and whose y axis is related to the values of the
individual row sums. A bell shaped curve will result whose peak
locates the reference line. If no reference line is located, the
test is terminated. If the reference line is located, then the
examination continues in order to locate the drug lines. The
detection of drug lines is more difficult because the amplitude,
i.e., dark or light, of its pixels can vary widely dependent on
several factors including wetting uniformity, urine color,
variations amongst test strips, exposure time, etc. In order to
compensate for these variations, each drug region is preferably
divided into left, center, and right portions. A drug line is
presumed to occupy the center portion of each region. However, its
exact position and exact width can vary attributable to the
aforementioned factors. Moreover, its brightness difference in
relation to neighboring areas can be very subtle. Hence, a
procedure is used to determine the weight of a line on a relative
basis.
[0031] For example, for each drug region graph, the total area
under each of three regions (left, center, right) is calculated.
The left and right region areas are then numerically summed, and
this resulting total area sum is multiplied by an experimentally
determined "weighting value," thus producing a weighted sum. If the
area of the center region is less than or equal to the weighted
sum, no line is present. By using urine samples with known drug
concentrations, a weighting value of 0.75 has been experimentally
determined to produce very acceptable results.
BRIEF DESCRIPTION OF THE FIGURES
[0032] FIG. 1 is a block diagram of a system in accordance with the
invention;
[0033] FIG. 2 is an isometric view of a preferred reader device in
accordance with the present invention;
[0034] FIG. 3 is an isometric view of a preferred cup and cap;
[0035] FIG. 4 is a plan view of the cap top surface;
[0036] FIG. 5 is a front sectional view taken substantially along
plane 5-5 of FIG. 2;
[0037] FIG. 6 is a top sectional view taken substantially along
plane 6-6 of FIG. 5;
[0038] FIG. 7 is a side sectional view taken substantially along
plane 7-7 of FIG. 5 showing the piston in its non-actuated
position;
[0039] FIG. 8 is a side sectional view similar to FIG. 7 showing
the piston in its actuated depressed position to force an aliquot
to the cap for wetting the test strips;
[0040] FIG. 9A is a sectional view taken substantially along the
plane 9A-9A of FIG. 5 primarily showing the cup interior;
[0041] FIG. 9B is an enlarged sectional view showing the aliquot
delivery mechanism of FIG. 9A in greater detail;
[0042] FIG. 10A is a diagrammatic view of a typical test strip used
in embodiments of the present invention;
[0043] FIG. 10B is a diagrammatic view of the test strip similar to
FIG. 10A but modified to represent rectangular regions used to
locate reference and drug lines;
[0044] FIGS. 10C and 10D depict steps employed in analyzing a cap
image to locate a strip reference line; and
[0045] FIG. 10E depicts a step employed in analyzing a cap image to
locate the presence of a strip drug line.
DETAILED DESCRIPTION
[0046] Attention is initially directed to FIG. 1 which depicts a
preferred system 20 in accordance with the invention comprised of
multiple service sites 22 respectively identified as 1 through N.
Each service site can operate independently as a stand-alone system
to perform a screening test, as will be described hereinafter.
However, in accordance with a preferred system configuration, the
multiple service sites are connected to a network 24, e.g., the
Internet, for communication with a host computer 26.
[0047] Each service site includes a reader device 28 configured to
cooperate with an assaying device 30 comprised of a specimen
collection cup 32 and a cap 34. FIG. 1 depicts a functional block
diagram of the reader 28 whereas FIGS. 2 and 4-7 illustrate the
reader's structural configuration. The structural configuration of
the assaying device 30 is illustrated in FIGS. 2-9.
[0048] Briefly, the reader 28 is comprised of a
processor/controller 36 programmed to operate (1) a camera 37 and
light source 38 via a camera interface circuit 40 and (2) a piston
motor 42 via a motor control circuit 44. As will be discussed
hereinafter, the piston motor 42 operates to deliver an aliquot
from a specimen in the cup 32 to one or more test strips in the cap
34. The test strips each produce a visible reaction in response to
being wetted by the aliquot. The camera 37 and light source 38
operate together to capture an image of the test strip(s) enabling
the processor/controller 36 to process the image to determine test
validity and whether the specimen is free of chemical components
being monitored. The reader 28 preferably operates in conjunction
with an input/output device 46 which enables a site attendant to
enter information, e.g., donor identification information, via a
device such as a touch pad or keyboard, and to view information,
e.g. via an LCD display, provided by the processor/controller
36.
[0049] The processor/controller 36 is also preferably connected to
the network 24 via a suitable connectivity device 48, e.g., a
modem. This enables the reader to upload data, e.g., test results,
billing information, etc. to the host computer 26. It also allows
the host computer to exercise supervisory control over the
processor/controller 36.
[0050] Attention is now directed to FIG. 2 which illustrates the
exterior configuration of the reader housing 60. The housing is
essentially comprised of a base portion 62, a head portion 64, and
an enclosure portion 66, bridging the base and head portions. A
receptacle 68 is defined between the base and head portions for
receiving an assaying device 30 above a keyed recess 70 formed on
base platform 72. The keyed recess 70 is shaped complementary to
the lower periphery of the assaying device 30 to place the device
in a specific orientation relative to head portion 64. The assaying
device 30 is comprised of an open collection cup 32 and a
detachable cap 34. The cup 32 defines an interior volume for
collecting a fluid specimen, e.g. urine. After the fluid specimen
has been deposited into the cup 32, the cap 34 is mounted thereon
to seal the interior volume and prevent the fluid specimen from
leaking. Inasmuch as each assaying device 30 is intended to be used
only once to collect a single specimen, it is preferably fabricated
via relatively low cost plastic molding processes.
[0051] It can be noted in FIG. 3 that the cup 32 has an irregular
lower periphery 76 particularly configured to mate with the keyed
recess 70. The periphery 76 includes an enlarged front portion 78
and a reduced rear portion 80. The reduced rear portion 80 is
bounded by fiat finger grip sides 82 having raised surface features
84 extending to an oblique wall surface 86. This irregular
configuration of the cup facilitates easy manual handling of the
cup enabling it to be readily grasped by the hand of a user and/or
administrator. The cup enlarged portion 78 preferably includes an
area 88 characterized by multiple vertical fins 90. This area 88
functions as a key or registration area to which an index area 92
on the cap 34 is aligned to assure proper cap/cup sealing. Markings
are preferably provided on the cup exterior to indicate maximum and
minimum fill levels.
[0052] Briefly, the cap 34 is comprised of a substantially circular
member 94 having a top exterior surface 96 and a depending flange
or skirt 98. The skirt 98 has a primarily knurled outer surface 100
that preferably defines flat areas 102 and the aforementioned index
area 92. The index area 92, which may be defined by vertical slots,
is preferably used to align with the aforementioned cup area 88 to
visually indicate to a user that the cap has been properly
installed onto the cup. The cap 34 is preferably installed onto the
cup via a mating thread 104. The cap 34 preferably carries a stop
tooth 107 which rotates into engagement with the end fin 90 when
the cap is properly installed onto the cup. When properly
installed, the cap index area 92 will be aligned with the cup
registration area 88. Alternative mounting mechanisms, e.g.,
bayonet mount, can be used to couple the cap 34 to the cup 32.
[0053] Provision is preferably made to include a tamper evident
seal to immediately indicate to a user whether an assaying device,
once sealed, has been tampered with. More particularly, note in
FIG. 3 that the cap top surface 96 carries a label 106 having a
first portion 108 permanently adhered to the surface 96. A second
label portion 110 extends beyond the edge of cap 34 and is intended
for sealing against cup area 111 immediately beneath the cup finned
area 88. The label portion 110 carries a suitable adhesive on its
undersurface which, prior to use, is protected by release paper
112. When the release paper is stripped away, label portion 110 can
be sealed against cup area 111 to assure that cap 34 cannot be
removed from cup 32 without that fact being immediately evident.
The label 106 preferably also includes a perforated tear-off third
portion 113 which can be affixed to a "B" container in case of
split specimen collections, or in the event that a manual chain of
custody record is required.
[0054] The cap top surface 96 (FIG. 4) is either transparent or at
least defines one or more transparent areas 114, e.g., windows
114A, 114B, and 114C for enabling a test strip mounted beneath each
window to be visible therethrough. As will be discussed
hereinafter, the cap defines one or more compartments each of which
accommodates a test strip 115 which, when wetted by a fluid
specimen, reacts to provide a visual indication indicative of a
characteristic of the specimen.
[0055] In the exemplary embodiment illustrated, the window 114C
covers a test strip intended to detect specimen (1) authenticity
and (2) adulteration. As is well known, a freshly voided urine
specimen can be authenticated by a test strip which senses various
characteristics including temperature and/or creatinine content of
the specimen. Adulteration of the specimen can be detected by a
test strip sensitive to exogenous components, e.g. pH and/or
nitrites. Preferably, the test strip changes color when wetted and
detection is achieved using a colormetric technique Larger windows
114A and 114B are intended to reveal test strips 115 for detecting
various specific chemical components typically associated with
illegal substance abuse. FIG. 10A schematically represents such a
component test strip 116 showing multiple latent lines 117 visually
represented on an indicator portion 118 extending from an absorbent
portion 119. The latent lines 11 7 typically include one or more
reference or control lines 117R and multiple drug lines 117D.sub.1,
117D.sub.2, etc., each for a different drug or chemical component
to be detected. If all of the lines visually appear within a
certain test interval, e.g., up to eight minutes, after the
absorbent portion 119 has been wetted, this will indicate the
absence of the specific chemical components sought (i.e., a
"negative" test). However, if any one of those specific chemical
components is present in concentration above a certain threshold,
its presence will suppress the appearance of one or more of the
lines to indicate to an astute observer and/or computer based
reader, the presence of that component.
[0056] The cap top surface 96 (FIG. 4) preferably additionally
defines a primary bar code area 120, a secondary bar code area 121,
and one or more fiducial marks 122, to be discussed hereinafter.
All of the windows 114, bar code areas, and fiducial marks are
arranged around a plunger hole 124 within a tightly dimensioned
image field 125 suitable for being imaged onto the focal plane of
camera 37. In an exemplary embodiment, the image field has width
and height dimensions respectively equal to 1446 mils and 1084 mils
which is imaged onto a camera view field having 640 pixels
horizontally and 480 pixels vertically.
[0057] The internal structure and operation of a suitable assaying
device 30 is described in aforementioned parent U.S. Pat. No.
6,342,183, whose disclosure is, by reference, incorporated herein.
Briefly, as depicted in FIGS. 5-9, the assaying device cap 34
defines descending concentric outer and inner tubular walls 126 and
127. Multiple passageways 128A, 128B, 128C, 1 28D extend vertically
between the outer and inner tubular walls 126 and 127. Each
passageway 128 defines a passageway inlet 129 at the lower end of
inner tubular wall 127 and a passageway outlet 130 proximate to
compartments 131, respectively accommodating component or
adulteration test strips 132, located beneath the aforementioned
windows 114. Overflow Basins 136, 138 are respectively located
adjacent to the compartments beneath windows 114A, 114B to collect
any fluid overflow.
[0058] The inner floor 150 of the cup 32 is configured to define an
open well 152. When the cap 34 is installed on the cup 32, the
lower end of the outer tubular wall 126 extends into the well 152
and essentially forms a closed chamber 154 for isolating a portion
of the fluid specimen. A plunger 160, comprised of a plunger pin
162 and plunger element 164, is mounted in inner tubular wall 127
above chamber 154. The plunger element 164, is formed of soft
conforming material able to seal against the inner surface of inner
tubular wall 127. The opening 124 in the cap top surface 96
provides access to enable the pin 162 to be depressed.
[0059] As the plunger element 164 is depressed into chamber 154,
the fluid therein is displaced upwardly via inlet 129 through
multiple passageways 128. These passageways, 128A, 128B, ] 28C, 1
28D respectively extend to the aforementioned test strip
compartments located below the aforementioned cap windows 114.
Thus, depression of the plunger 160 within the inner tubular wall
127 displaces fluid from the chamber 154 to deliver an aliquot to
each of the compartments 131, each compartment accommodating a
separate strip 115 of test material. The device 30 is constructed
and dimensioned so that each aliquot comprises a specific volume of
fluid.
[0060] Attention is now directed to FIGS. 5-8 which illustrate the
internal structure of the reader housing 60. The housing 60 is
formed by a base plate 150 having a vertical frame member 152
secured thereto. The base plate 151 is weighted by block 154 for
stability. A shell 160 is affixed to the base plate 150 and frame
member 152. The shell includes a base platform member 72 which
defines the aforementioned keyed recess 70. The shell 160
additionally includes a rear shell member 162 which encloses a rear
compartment 164 housing the reader electronic circuit board(s) 166.
An upper shell member 170 encloses a top compartment 172 which
houses the camera 37, light source 38 and piston motor 42. These
devices are structurally supported on arm 176 projecting forwardly
from frame member 152.
[0061] A piston subassembly 180 is mounted for vertical reciprocal
motion toward and away from base plate 150. The piston subassembly
is comprised of a support arm 182 projecting forwardly from slide
block 184 mounted for linear movement along guide rails 186. The
support arm 182 carries a piston member 186 aligned with opening
124 in the cap of an assaying device 30 placed in the keyed recess
70. A lead screw 188 is threaded into hole 190 in support arm 182.
The lead screw can be selectively rotated either clockwise or
counterclockwise by piston motor 42 to move the slide block 184
either up or down. FIG. 7 depicts the piston member 186 in its up
position providing sufficient clearance to allow an assaying device
30 to be placed on or removed from the keyed recess 70. FIG. 8
shows the piston member 186 in its down position extending into cap
opening 124 to depress plunger 160 to displace fluid from the
specimen in cup 32 to wet the test strips 115.
[0062] It should also be noted that the piston subassembly 1 80
includes a substantially cylindrical light shield 192 mounted on
slide block 184. The light shield 192 defines a lower edge 194
which seals against the cap top surface 96 when the slide block is
in its down position shown in FIG. 8.
[0063] The camera 37 can comprise a commercially available digital
camera and appropriate optics for imaging the field 125 (FIG. 4)
onto the camera's focal plane. The camera preferably has a
resolution of 640 (horizontal).times.480 (vertical) pixels. Imaging
is enhanced by selective illumination of light sources 38 and by
the shielding effect afforded by light shield 192.
[0064] A preferred operational sequence for automatically testing a
fluid specimen is represented by the following sequential steps:
[0065] 1. Donor at a local site deposits fluid into cup 32; site
administrator enters identification information and secures cap 34
in tamper evident fashion; [0066] 2. Administrator places cup/cap
into "keyed" receptacle 70 of local reader 28 and enters ID
information; [0067] 3. Reader 28 alerts host computer 26 via
communication network 24; [0068] 4. Host computer 26 (or
administrator) initiates reader operational sequence: [0069] a.
camera 37 captures cap image and processor 36 verifies
acceptability to proceed [0070] b. processor 36 runs piston motor
42 to advance piston 164 into cup to force fluid up channels 128 to
wet component and adulteration test strips [0071] c. camera
captures additional cap image and verify acceptability to proceed
[0072] d. periodically capture additional cap images during
development interval tip to about eight minutes [0073] e. processor
analyzes captured image data to determine [0074] 1. test validity
[0075] 2. test results [0076] f. processor 36 displays test
validity/results on local I/O 46 and/or communicates test
validity/results to Host computer 26 [0077] g. processor 36 runs
piston motor to withdraw piston from cup [0078] 5. Site
administrator removes cup from reader
[0079] In step 1, the site administrator first enters donor and
client (e.g., employer) information via I/O devices 46 into a
database stored either in processor 36 or host computer 26. The
donor voids into a cup 32 and the cap 34 is sealed thereon. The
label is extended from the cap to the Cup to assure that it is
sealed in tamper evident fashion. Preferably the administrator and
donor then initial the sealed label and review the chain of custody
document. The donor and administrator both apply their signatures
to the signature pad and a copy of the chain of custody document is
printed and given to the donor. The donor is then dismissed.
Preferably the cup/cap is then placed in the reader.
[0080] Step 4 of the foregoing sequence is automatically executed
under the control of programmed microprocessor 36. In step 4a, the
piston has not yet been inserted into the cup and may partially
obscure the field of view. In addition, since the piston is not
down, the light shield is only partially effective, and extraneous
light may enter, further obscuring details. Nevertheless, an
initial image is captured by the camera to examine the primary
barcode 120 and other cap features to determine if it is valid. If
the barcode is not valid, this fact is displayed to the site
administrator for further action. An invalid barcode can indicate
that the cup is inserted incorrectly, that there is no cup there at
all, or that a "fake" cup has been inserted. If the administrator
cannot resolve the issue and the barcode is indeed invalid, testing
is aborted and the sealed cup is sent for laboratory analysis.
[0081] In step 4b, processor 36 runs the piston motor 42 to lower
the piston 164 a predetermined distance. This also lowers the light
shield 192 into place against the cap top surface 96 so that the
light source 38 is then the only source of light illuminating the
cap top. The light source 38 preferably comprises multiple green
LED's inasmuch as the lines that appear on typical component test
strips exhibit the highest contrast when viewed in green light.
With the piston in its down position, it no longer obscures any cap
features within the image field 125.
[0082] In step 4c, another image of the cap is captured and
processed to double-check the primary barcode results from the
previous step and to read the secondary barcode 121 and the
fiducial marks 122. The fiducial marks 122 are small features
printed on the cap directly above the test strip windows 114A, 114B
and serve as reference points for subsequent processing steps to
assure accurate image analysis. Preferably, the barcode labels have
their own fiducial marks, which allow the barcodes to be found and
read even if the label is askew. If all barcodes and fiducial marks
can be located and properly read, then operation proceeds to step
4d. Otherwise, the site administrator is alerted and he/she decides
whether to proceed or not.
[0083] The test strips take between two and eight minutes to
develop. During step 4d, images are periodically captured and
during step 4e, the images are processed and analyzed. Steps 4d and
4e are executed in an iterative loop. If all latent lines become
visible after two minutes, the test is concluded and operation
proceeds to step 4f. Otherwise steps 4d and 4e are executed every
minute until eight minutes have elapsed. If any of the drug or
control lines do not become visible, the assaying device is sent to
the lab for further analysis.
[0084] The image analysis executed in step 4e includes an extensive
procedure to be discussed hereinafter for discerning a color change
on the adulteration test strip and visible reference and drug lines
on the component test strip. The detection of these lines can be
reasonably challenging because the amplitude, i.e., dark or light,
of its pixels can vary widely dependent on several factors
including variations in test strips, in wetting, in urine color,
etc. In order to produce an optimum image for analysis, a sequence
(e.g., 8) of images is actually captured. These multiple images are
then mathematically summed divided by the number of images in order
to produce an integrated image in which the random electrical and
optical "noise" has been reduced by this "averaging" process. This
integrated image is then used in the subsequent line detection
procedure: [0085] 4e(1) The fiducial marks 122, which had been
found to exist in step 4c, are now located precisely by looking in
a restricted region (as a consequence of the cup being physically
positioned by keyed recess 70) and finding the centroid of the
individual fiducial marks. This determines their exact locations
within the camera field of view (i.e., 640.times.480). [0086] 4e(2)
Based on the locations of the fiducial marks, the image is now
rotated, translated, minified, and or magnified as necessary so
that the resulting image has the fiducial marks 122 (and hence all
other cap features) in "standard" positions which is hence presumed
for all subsequent operations. [0087] 4e(3) Using a "map" of the
features present on the cap top, each test is individually
examined. Although the two test strips can in fact differ in the
number of lines present and their specific locations, for the sake
of simplicity, the operations on only one typical test strip will
be described. [0088] 4e(4) Based on known default reference and
drug line positions, non-overlapping rectangular regions 200 are
"drawn" around each reference line 117R and drug line, e.g., 117D
(FIG. 10B). [0089] 4e(5) For the region 200 which contains the
reference line 117R, row sums are produced.
[0090] The number of pixels summed for each row is the "width" of
the test strip (e.g., 32 in FIG. 10C), the number of total row sums
for each region is the "height" of the individual region (e.g., 48
in FIG. 10C). Each of these row sums produces a graph (FIG. 10D)
whose X axis is related to the "height" of the region, and whose Y
axis is related to the values of individual row sums. Let it be
assumed that individual row sums will be smaller for darker
horizontal rows and larger for lighter horizontal rows. The
resulting graphs are then preferably normalized so that the Y axis
values are between 0 and 100, and then subtracted from 100 so that
the darkest row in a given region has the value 100 and the
brightest row in a given region has the value 0. Bell shaped curves
will result (presuming a drug or control line is present) as
depicted in FIG. 10D. [0091] 4e(6) The reference line 117R must be
located in order to proceed further and its exact position must be
determined in order to locate the best estimated positions of the
drug lines for further processing. The graph for the reference line
is examined for a maximum value, which represents the reference
line center position. After the center position is located, the
regions drawn in substep 4e(4) above are redrawn to center the
reference line and drug lines in their respective regions. [0092]
4e(7) For each drug region, row sums and the resulting graph are
produced as described in substep 4e(5) above. [0093] 4e(8) Each
drug region graph is divided into three equal parts, a left,
center, and right part as represented in FIG. 10F. The drug line is
presumed to occupy the center portion. However, its exact position
and width can vary, and its brightness difference in relation to
the neighboring area may be very subtle. Based on different wetting
conditions, a dark condition in one region can in fact be lighter
than a not-dark condition in another region. Hence, a relative
mechanism is used to determine the presence or absence of a drug
line. [0094] 4e(9) For each drug region graph, the total area under
each of the three regions (left, center, right) is calculated. The
left and right region areas are then numerically summed, and this
resulting total area sum is multiplied by an experimentally
determined "weighting value", thus producing a weighted sum. If the
area of the center region is greater than this weighted sum, a
decision is made that a line is present. If the area of the center
region is less than or equal to the weighted sum, a decision is
made that no line is present. By using urine samples with known
drug concentrations, a weighting value of 0.75 has been found to
produce very acceptable results. In order to conceptually
understand what is going on, presume that the graph is perfectly
symmetric and the drug line is centered in the graph, hence the
graph will appear as a bell curve (FIG. 10F) (this is typical of
the actual graphs produced) if a line is present, or at the other
extreme, will appear as a flat line if no drug line is present. In
the case of a flat line, then the summed areas of the left and
right region will be exactly twice (2*X) the area of the center
region (X). If the 2*X value is weighted by 0.75, the resulting
area is now 1.5*X, which is greater than X. Hence no drug line is
considered present. In fact, the weighting value would have to be
less than 0.5 for a line to be considered present. As the center
region grows in amplitude, its area reaches a point that it is now
greater than the weighted sum of the left and right regions, and a
line is considered present. Note that the presence or absence of a
line is not determined by the exact position or shape of this
curve, nor by the exact amplitudes of the dark and light
components, which can vary widely based on various factors
including the degree of wetting, the color of the urine, the
particular lot of test strips, the time of exposure, extraneous
material on the test strip, and shadows and/or reflections. All of
these variations are compensated for in the relatively simple and
concise mathematical procedure described which allows the presence
or absence of drug lines to be repeatedly determined to a
controllable, high degree of accuracy.
[0095] Once all adulteration test strips have been examined for
color and all component test strips examined for visible lines, a
final test result, for adulteration and identification of drug
lines present and/or absent, is locally displayed and/or
communicated to the host computer in accordance with aforementioned
step 4f.
[0096] The foregoing describes applicants' preferred system for
automatically testing fluid specimens to detect specific chemical
components therein. The preferred system includes an assaying
device comprised of a fluid collection cup and a cap carrying one
or more test strips configured to produce visually discernable
indications of the components of the specimen and/or specimen
adulteration. The visual indications are read by an imager, e.g.,
digital camera, and interpreted by a processor which executes an
analysis procedure to interpret the visual indications. The
resulting test results are reported locally or via a communications
network to a host computer. Thus, systems in accordance with the
invention can quickly (e.g., in less than 15 minutes) and locally
automatically test a fluid specimen to provide accurate qualitative
test results. The system both assures the confidentiality of
donor/specimen test results (by using machine readable, rather than
human readable, markings) and a closely controlled chain of custody
procedure.
[0097] Although a preferred embodiment has been described, it is
understood that many modifications and variations will occur to
those skilled in the art which fall within the intended scope of
the invention as defined by the appended claims.
* * * * *