U.S. patent application number 16/812959 was filed with the patent office on 2020-09-03 for method and apparatus for performing hematologic analysis using an array-imaging system for imaging and analysis of a centrifuged.
The applicant listed for this patent is David A. Clipper, Joshua D. Levine, Robert A. Levine, Craig Stout, Stephen C. Wardlaw. Invention is credited to David A. Clipper, Joshua D. Levine, Robert A. Levine, Craig Stout, Stephen C. Wardlaw.
Application Number | 20200278341 16/812959 |
Document ID | / |
Family ID | 1000004830043 |
Filed Date | 2020-09-03 |
![](/patent/app/20200278341/US20200278341A1-20200903-D00000.png)
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United States Patent
Application |
20200278341 |
Kind Code |
A1 |
Levine; Joshua D. ; et
al. |
September 3, 2020 |
METHOD AND APPARATUS FOR PERFORMING HEMATOLOGIC ANALYSIS USING AN
ARRAY-IMAGING SYSTEM FOR IMAGING AND ANALYSIS OF A CENTRIFUGED
ANALYSIS TUBE
Abstract
A method and device for analyzing a hematologic sample
centrifuged within a capillary tube is provided. The device
includes a tube holder, a sample imaging device, a processor, and a
sample data display. The sample imaging device is operable to
create a digital image of the sample within a region of the tube.
The region is defined by substantially all of the radial width and
axial length of the sample residing within the internal cavity of
the tube in the region where the float resides after
centrifugation. The sample imaging device is operable to produce
signals representative of the image. The processor is adapted to
produce information relating to bands of interest within the image
based on the signals from the sample imaging device. The sample
data display is adapted to display the results therefrom and/or a
digital image of the sample within the region.
Inventors: |
Levine; Joshua D.; (Chapel
Hill, NC) ; Levine; Robert A.; (Guilford, CT)
; Wardlaw; Stephen C.; (Lyme, CT) ; Stout;
Craig; (Port Matilda, PA) ; Clipper; David A.;
(State College, PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Levine; Joshua D.
Levine; Robert A.
Wardlaw; Stephen C.
Stout; Craig
Clipper; David A. |
Chapel Hill
Guilford
Lyme
Port Matilda
State College |
NC
CT
CT
PA
PA |
US
US
US
US
US |
|
|
Family ID: |
1000004830043 |
Appl. No.: |
16/812959 |
Filed: |
March 9, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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15207074 |
Jul 11, 2016 |
10585084 |
|
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16812959 |
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13016347 |
Jan 28, 2011 |
|
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15207074 |
|
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61351138 |
Jun 3, 2010 |
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61305449 |
Feb 17, 2010 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01L 2300/0654 20130101;
G01N 2800/22 20130101; G01N 15/05 20130101; B01L 2300/0838
20130101; G01N 2015/045 20130101; B01L 2300/0609 20130101; G01N
15/042 20130101; G06T 2207/30024 20130101; B01L 9/065 20130101;
G01N 33/491 20130101; B01L 2300/027 20130101; G06T 7/0012 20130101;
B01L 3/50215 20130101 |
International
Class: |
G01N 33/49 20060101
G01N033/49; B01L 3/00 20060101 B01L003/00; G01N 15/04 20060101
G01N015/04; G01N 15/05 20060101 G01N015/05; B01L 9/06 20060101
B01L009/06; G06T 7/00 20060101 G06T007/00 |
Claims
1. A method for analyzing a hematologic sample, comprising:
disposing the hematologic sample within an internal compartment of
a capillary tube, which internal compartment has a radial width and
an axial length and a float disposed within the capillary tube;
providing a centrifuge and a sample imaging device; using a
processor to execute instructions stored within a memory device,
which instructions cause the processor to: control the centrifuge
to centrifugally spin the capillary tube containing sample about a
central axis at speeds sufficient to create constituent layer
separation within the sample disposed in the at least one capillary
tube; control the sample imaging device to create a digital image
of a sample region of the sample disposed within the tube, which
sample region extends across all of the radial width and axial
length of the internal compartment of the tube in a region of the
tube where the float resides after centrifugation, and produce the
signals representative of the digital image; produce information
relating to the digital image based on the signals from the sample
imaging device; and control a sample data display to display the
information relating to the digital image of the sample region.
2. The method of claim 1, wherein the capillary tube is attached to
a platen portion of the centrifuge in a position where the
capillary tube extends radially outward from the central axis.
3. The method of claim 1, wherein the sample imaging device
includes a digital camera.
4. The method of claim 1, wherein the instructions when executed by
the processor, cause the processor to control the sample data
display to display the digital image of the sample region.
5. The method of claim 4, wherein the instructions when executed by
the processor, cause the processor to control the sample data
display to display superimposed graphic markings based on an
analysis of the sample over the digital image to illustrate band
boundaries.
6. The method of claim 5, wherein the graphic markings are
superimposed to identify at least one of a bottom of the tube, a
bottom of the float, a red blood cell/granulocyte interphase, a
granulocyte/lymphocyte and monocyte interphase, a lymphocyte and
monocyte/platelet interphase, a platelet/plasma interphase, a top
of the float, or a plasma/air interphase.
7. The method of claim 1, wherein the information relating to the
image based on the signals from the sample imaging device includes
complete blood count information.
Description
[0001] This application is a divisional of U.S. patent application
Ser. No. 15/207,074 filed Jul. 11, 2016, which is a continuation of
U.S. patent application Ser. No. 13/016,347 filed Jan. 28, 2011,
which claims the benefit of U.S. Provisional Patent Application No.
61/305,449 filed Feb. 17, 2010 and U.S. Provisional Patent
Application No. 61/351,138 filed Jun. 3, 2010, each of which
applications is hereby incorporated by reference in its
entirety.
BACKGROUND INFORMATION
[0002] U.S. Pat. Nos. 4,027,660; 4,091,659; 4,137,755; 4,209,226;
4,558,947; 4,683,579; 5,132,087; 5,888,184; and 6,441,890 describe
methods and apparatus for hematological analysis using a capillary
tube and a space occupying insert that floats on the centrifuged
red blood cells thereby expanding the surrounding buffy coat and
permitting the measurement and quantization of the blood's layers.
This method permits the determination of a compete blood count
(CBC) consisting of hematocrit, a hemoglobin determination, a total
white blood cell count with the latter presented as a total and
percent granulocytes and total and percent lymphocytes plus
monocytes, as well as a platelet count and a mean red cell
hemoglobin concentration. It is widely used through the world for
performing point of care CBC in human and veterinary medicine. The
device, formerly manufactured and sold by Becton Dickinson, Inc. of
New Jersey U.S.A. is now manufactured and sold by QBC Diagnostics,
Inc., of Pennsylvania, U.S.A. The apparatus is sold under the
trademark of QBC.RTM. hematology. The capillary tubes are referred
to in the industry as "QBC.RTM. tubes".
[0003] The QBC.RTM. hematology system includes a number of
different complex instruments for reading the QBC.RTM. tubes, each
of which has an illumination system, a power source, an imaging and
optical system, a microprocessor, and a display. These devices can
cost anywhere from several hundred to many thousands of U.S.
dollars. The current versions of both the stand-alone reader and
the integral reader-centrifuge (QBC.RTM. STAR reader) provide for a
linear scan of the tube, either while it is stationary in the case
of the stand-alone reader or while the centrifuge is in motion, as
is the case with the QBC.RTM. STAR reader. In both cases, the
linear scan is limited to scanning a single axially extending line
scan of the tube, which evaluates only a thin stripe of the area of
interest within the tube. Because this method of scanning can only
scan a thin stripe of the area of interest at a given time, it is
necessary to take multiple axially extending scans taken at
different circumferential positions of the tube to determine which
of the scans can be used for analytical purposes. By looking at
several different scans, each taken at a different circumferential
position, it is possible to ascertain whether any particular scan
is representative of the sample or if it contains an
unrepresentative anomaly. Also, because of the narrow scan, the
mechanical and optical alignment of the instrument must be held to
a very high tolerance, which also increases the cost of the
device.
[0004] This is particularly true in the case of the QBC.RTM. STAR
reader, because the QBC.RTM. tube is read while the centrifuge is
in motion, necessitating an elaborate timing system to ensure that
illumination occurs exactly when the tube is in position under the
linear scanning device (e.g., CCD scanner). Another, related
problem is the need to provide elaborate vibration damping so that
the relative tube and reader position be maintained during this
process.
[0005] These considerations force the analysis tube readers to have
a relatively high price, which limits the market size for the
QBC.RTM. hematology system because health care providers are
reluctant and/or unable to make the requisite equipment investment
when the equipment is only used for a few tests per day. In those
instances when the point of care giver does not have the analysis
equipment, the patient is subjected to the significant
inconvenience, harm and expense of having to go to a private
laboratory and having to wait often several days to get the result.
The lack of an analysis device also makes the physician's job more
difficult by precluding immediate results at the point of care.
Additionally, regulatory requirements of the United States require
that the providers of the test be subject to regulatory supervision
under the CLIA (Clinical Laboratory Improvement Act) laws.
[0006] What is needed, therefore, is a simple, inexpensive, robust
method for reading the centrifuged blood sample at the point of
care with immediate availability of results while the health care
providers are still with the patient. In addition, a method and
device are needed that can provide accuracy results and
methodological adherence to proper analytic techniques, as well as
quality control measures, particularly those that will permit CLIA
waiving, which is subject to less burdensome regulations.
SUMMARY OF THE INVENTION
[0007] According to one aspect of the present invention, a device
for analyzing a hematologic sample centrifuged within a capillary
tube is provided. The tube has an internal compartment with a
radial width and an axial length and a float disposed within the
tube. The device includes a tube holder, a sample imaging device, a
processor, and a sample data display. The sample imaging device is
operable to create a digital image of the sample within a region of
the tube. The region is defined by substantially all of the radial
width and axial length of the sample residing within the internal
cavity of the tube in the region where the float resides after
centrifugation. The sample imaging device is operable to produce
signals representative of the image. The processor is adapted to
produce information relating to bands of interest within the image
based on the signals from the sample imaging device. The sample
data display is adapted to display the results therefrom and/or a
digital image of the sample within the region.
[0008] According to another aspect of the present invention, a
method of analyzing a hematologic sample deposited within a
capillary tube is provided. The tube has an internal cavity with a
radial width and an axial length, and a float disposed within the
tube. The method includes the steps of: a) centrifuging the sample
to create constituent bands within the sample disposed in the tube;
b) creating an image of a region of the centrifuged sample, which
region is defined by substantially all of the radial width and
axial length of the sample residing within the internal cavity of
the tube in a region where the float resides after centrifugation;
c) determining a position for one or more band boundaries using the
image; and d) producing analysis results based on the determined
band boundaries.
[0009] Advantages associated with the present analysis device
include the provision of a less expensive, and easier to
manufacture, analysis device. The imaging of substantially all of
the radial width and a significant portion of the axial length of a
centrifuged sample within a capillary tube eliminates many problems
associated with narrow linear array sensing. For example, prior art
linear array sensing is susceptible to circumferentially located
bandwidth anomalies; e.g., if the bandwidth at a particular
circumferential position is irregularly too small or too big, data
based on that band width will be inaccurate. For this reason, the
prior art devices take multiple linear array sensings at
non-contiguous circumferential positions and average those
sensings, or otherwise compare them to one another for accuracy.
The prior art devices, therefore, require hardware that can rotate
one or both of the linear sensing array and the sample. The
hardware must also be able to provide very accurate mechanical and
optical alignment of the instrument relative to the sample, and in
the case of a dynamic sensing device like the QBC.RTM. STAR reader,
also provide elaborate imaging controls and vibration damping. The
present device also provides significant quality control
mechanisms.
[0010] On the other hand, the prior art linear imaging had the
advantage of minimal geometric distortion. Since all prior art
imaging data was in the form of a narrow linear segment taken at a
right angle to the tube as it was scanned, each band position was
exactly related to its digital representation. In the case of the
image array as used in the present device, in which the tube is
positioned some distance from the imaging lens and camera, the
bands in the tube are foreshortened in proportion to their distance
from the center of the optical axis, and the sides of the tube are
particularly affected by this effect, sometimes making them appear
crescent shaped. This geometric distortion, in addition to any
other distortions from the lens, is preferably accounted for in
order to enhance the accuracy of the results. For example, the
geometric distortion can be accounted for by using a correction
table which accounts for each pixel, or regions in the image. The
correction table can be used to re-map the image so that the image
positions correctly correspond to the actual locations on the tube
surface. This type of correction table can be automatically
generated by imaging and analyzing a known `calibration` standard
or if only geometric distortion is involved, the corrections can be
simply calculated based on the known distances involved.
Alternatively, the geometric distortion can be accounted for by
correcting the band lengths following their preliminary
measurement.
[0011] The foregoing and other objects, features and advantages of
the present invention will become more apparent in light of the
following drawings and detailed description of the present
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a schematic diagram of the present invention
hematology analysis device.
[0013] FIG. 2 is a schematic diagram of a capillary tube.
[0014] FIG. 3 is an enlarged partial view of a tube such as that
shown in FIG. 2.
DETAILED DESCRIPTION OF THE INVENTION
[0015] Referring to FIGS. 1-3, a blood sample for analysis within
the QBC.RTM. hematology system is typically obtained either from a
venous or capillary sample, centrifuged in a simple, small
dedicated centrifuge which may be either battery powered or AC
powered. U.S. Pat. Nos. 4,027,660; 4,683,579 and 6,441,890, each of
which is hereby incorporated by reference in its entirety, describe
methods and apparatus for hematological analysis using a capillary
tube and a space occupying insert that floats on the centrifuged
red blood cells thereby expanding the surrounding buffy coat and
permitting the measurement and quantization of the blood's layers.
The capillary tube 10 includes a body that extends between a closed
bottom 12 and an open top 14. In some embodiments, the "closed
bottom" may be vented to allow the escape of gas. The open top 14
provides access to an internal cavity 16 that has a radial width 18
and an axially extending length 20. In those embodiments where the
tube 10 is cylindrical, the radial width 18 is the inner diameter
of the tube 10. The present invention is not limited to use with
any particular type of capillary tube. U.S. Pat. No. 4,027,660, for
example, describes a QBC.RTM. style capillary tube operable to
contain a fluid sample and a volume occupying mass 22 (hereinafter
referred to as a "float"), and the information available by virtue
of the relative positioning of the float 22 within the sample after
centrifugation. U.S. Pat. No. 6,444,436 describes a different style
of capillary tube that can be used with the present invention;
e.g., one having a polynomial (e.g., rectilinear) cross-sectional
geometry. FIGS. 2 and 3 of the present application diagrammatically
illustrate a capillary tube 10 with a sample and a float 22
disposed in the internal cavity 16 of the tube 10. The centrifuged
sample disposed in the tube 10 illustrates the constituent bands 24
(24a, 24b, 24c, 24d, 24e) and the band boundaries 25 (25a, 25b,
25c, 25d) therebetween. U.S. Pat. Nos. 4,683,579 and 6,441,890
describe automated devices for reading the centrifuged sample by
way of an axially extending linear scan of a limited portion of the
sample disposed within the QBC.RTM. tube, which limited linear
portion is disposed at a particular circumferential position of the
tube 10.
[0016] The present invention analysis device operates with a
capillary tube 10 such as those provided within a QBC.RTM.
hematology system; i.e., a tube 10 filled with a sample that has
been centrifuged to produce the separated constituent layers (i.e.,
"bands") 24 within the sample. One embodiment of the present
analysis device 28 includes a housing 30 containing a tube holder
32, a sample imaging device 34, a processor 36 adapted to produce
information relating to bands 24 of interest within the image based
on the signals from the sample imaging device 34, a sample data
display 38, and may include an operator input device 40 that
enables the operator to enter relevant patient information.
[0017] In some embodiments, the analysis device 28 further includes
a centrifuge 42 with a platen 44 configured to hold one or more
capillary tubes 10 in a position where the tubes 10 extend radially
outward from a central axis. In these embodiments, the analysis
device 28 can perform both the centrifugation and the image
analysis. The centrifuge 42 is operable to centrifugally spin the
tube 10 containing the sample about the central axis at speeds
sufficient to create constituent layer separation within the sample
disposed in the tube 10. In these embodiments, the platen 44 is an
example of a tube holder 32. In other embodiments, the tube holder
32 may be independent of the centrifuge 42.
[0018] The sample imaging device 34 includes a digital camera
operable to image substantially all of the radial width 18 and
axial length 20 of the sample residing within the internal cavity
16 of the tube 10 in the region 46 (see FIG. 3) where the float 22
resides after centrifugation in a single image, and to produce
signals representative of the image. In the preferred embodiments,
the sample imaging device 34 is operable to image a region 48
comprising substantially all of the radial width 18 and axial
length 20 of the sample within the tube 10 in a single image, and
to produce signals representative of the image. Alternately, two or
more cameras can be used to image separate portions of the tube 10,
which portions are contiguous with one another. The images of the
contiguous regions can be subsequently combined and analyzed or are
separately analyzed. Either the digital camera itself, or an
independent light source within the sample imaging device 34,
provides sufficient lighting so that bands 24 of interest within
the centrifuged sample may be differentiated within the sample
image. The optical resolution of the camera must be sufficient to
provide adequate clarity within the image for the analysis at hand;
e.g., to differentiate bands 24 of interest. As indicated above,
the sample imaging device 34 may be incorporated into a QBC.RTM.
tube type reader, or may be an independent device (e.g., a portable
digital camera, a cell phone camera, etc.) configured for use with
such a reader. An example of an acceptable digital camera is a
Bayer-type matrix color camera. If, for example, a standard
Aptina.RTM. five megapixel color camera chip with a frame width of
2592 pixels is used, it can produce a theoretical image resolution
of 0.02 mm, which is acceptable for most analyses. If a color
camera is used, color filters and different illumination types are
likely not required. A grey scaled camera may also be used because
the separated buffy coat layers have different light scattering
properties and may therefore be detected using a black and white
camera, although this measurement is less robust and requires more
controlled illumination. The sample imaging device 34 may be
described as an "area-array imaging device" because it images
substantially all of the radial width 18 and axial length 20 of the
sample within the interior cavity 16. If a plurality of cameras is
used within the present sample imaging device 34, the images they
produce are contiguous with one another thereby permitting the
plurality of images to be combined into a single representative
image. The linear scan devices of the prior art, in contrast, are
limited to producing narrow linear segments that do not extend
across the full radial width 18, and the circumferential linear
segments are not contiguous with each other. As a result, the
circumferentially positioned linear segments cannot be combined
into a single representative image. Examples of acceptable
independent light sources include white and/or blue LEDs, operable
either in a steady state mode or in the case of the QBC.RTM. STAR
type reader, in a pulsed mode. The relative blue spectrum of a
white LED or the inclusion of a separate blue LED can excite the
fluorescence of a dye such as Acridine Orange in the tube 10.
[0019] The processor 36 is adapted (e.g., programmed) to perform
several tasks, including: a) controlling the sample imaging device
34 based on the analysis at hand; b) controlling the centrifuge 42
for those embodiments that include one; c) receiving and acting on
operator input entered through the operator input device 40; and d)
producing information relating to bands 24 of interest within the
image based on the signals from the sample imaging device 34. The
extent of the information relating to the bands 24 can vary
depending upon the embodiment of the device 28. For example, the
processor 36 may be adapted to provide information relating to the
adequacy of the sample image, and/or with algorithmic capability
that is operable to analyze the signals representative of the
sample image and produce data (e.g., CBC, hematocrit, WBC count,
etc.) relating thereto based on characteristics of the different
bands 24 within the centrifuged sample. In some applications, the
processor 36 can be adapted to produce graphic markings based on
the analysis of the sample that can be superimposed over the sample
image when displayed to illustrate the calculated band boundaries
25 relative to the sample image. Using the analysis of a blood
sample as an example, graphic markings can be used to identify
features such as the: a) bottom of the tube 10; b) bottom of the
float 22; c) red blood cell/granulocyte interphase; d)
granulocyte/lymphocyte and monocyte interphase; e) lymphocyte and
monocyte/platelet interphase; f) platelet/plasma interphase; g) top
of the float 22; h) plasma/air interphase; etc.
[0020] The sample data display 38 is in communication with the
processor 36 and includes a display screen. The display screen is
an electronic screen (e.g., flat screen LED, LCD, etc.) operable to
display the calculated results and/or a digital image of the sample
residing within the centrifuged sample with sufficient optical
resolution so that the image can be evaluated by a technician
operator to provide the information pertaining to the bands 24 of
interest within the centrifuged sample. In those embodiments that
include an operator input device 40 (e.g., key pad, touch screen,
etc.), the operator input device 40 allows the operator to enter
relevant patient or other information, if desired. The sample
display 38 may be integral with the housing 30, or it may be an
independent device in communication with the processor 36. For
example, universal monitors are often used in medical facilities,
which monitors have the capability of displaying data from more
than one analysis device. In such an application, the data to be
displayed may be viewed on an integral display screen and/or a
remotely located display device in communication with the processor
36.
[0021] In some embodiments, the analysis device 28 includes a
communication port 50 for sending the signals representative of the
sample image to a remote location. The communication port 50 can be
a hardwire port for communicating by hardwire connection to a
remote site, or it can be a wireless communication connection
(e.g., similar to that used in a wireless phone).
[0022] In some embodiments, fiduciary marks 52 (i.e., calibration,
measurement marks, etc.) may be placed on or in the capillary tube
10, or the tube holder 32, or on a measuring device positioned
adjacent the tube 10 (e.g., a ruler) to facilitate geometric and/or
optical calibration and thereby account for any image distortion
introduced by the camera. In those instances where the fiduciary
marks are placed on or in the tube, a particularly useful
embodiment is one wherein the marks are positioned relative to the
internal cavity to permit geometric evaluation of sample within the
internal cavity. In those instances where fiduciary marks 52 are
disposed on a measuring device positioned adjacent the tube 10, the
measurement device can measure along an axis that is maintained
parallel to the lengthwise axis (e.g., axial direction) of the tube
10. In such embodiments, the measurement device is preferably in
close proximity (e.g., in the same focal plane) as the sample tube
10. Alternately, a look-up-table can be provided by factory
calibration to serve this function. During the image processing and
analysis steps, the calibration information can be used to ensure
correct length measurements of the tube 10 features, regardless of
their position in the image frame or distance from the camera and
can compensate for instrument-to-instrument differences.
Operation:
[0023] A fluid sample (e.g., whole blood) is collected from a
patient and deposited into a capillary tube 10 such as those used
in the QBC.RTM. hematology system for subsequent centrifugation. As
indicated above, the centrifuge may be independent of, or
incorporated into, the analysis device 28. The sample is
centrifuged for a period of time adequate to create constituent
layer separation within the sample disposed in the tube 10, and the
representative bands 24 associated therewith. The centrifuged
sample is then imaged using the sample imaging device 34. The image
includes substantially all of the radial width 18 and axial length
20 of the sample residing within the internal cavity 16 of the tube
10 in the region where the float 22 resides after centrifugation.
Because capillary tubes 10 are not always filled with the exact
same volume of fluid sample, the sample imaging device 34
preferably images the region 48 of the tube 10 from the top
meniscus to the bottom of the red blood cell layer. It is
desirable, but not required, that the bottom of the tube 10 be
imaged as well. If the sample being imaged is disposed within a
STAR type QBC.RTM. tube, for example, the total length between the
tube bottom to the tube top fill position is approximately 53 mm.
The distance from the tube top fill position to the bottom of the
float 22 in most instances is about 37 mm. In those device 28
embodiments that include a centrifuge, the sample may be
centrifuged and the centrifuge subsequently stopped or slowed to a
very low RPM prior to the imaging. The sample imaging device 34
produces signals representative of each image and communicates
those signals to the processor 36.
[0024] The images signals are subsequently analyzed within the
processor 36 using image processing algorithms to isolate and
analyze the bands 24 of interest within the sample, and in some
instances relevant sections of the bands 24. Before or after the
image signals are analyzed, the image signals may be sent to the
sample data display 38 for evaluation by the operator. The ability
to have an operator visually evaluate an image that includes
substantially all of the radial width 18 of the sample within the
tube 10, and a relevant portion of the axial length 20 of the
sample is a substantial advancement of the technology. A person of
skill in the art will recognize that no automated system can
account for all potential variables within the sample image. For
example, during the centrifugation process, there is a chance that
sample will exit the capillary tube 10 and pass into the retaining
tube of the centrifuge. In such instances, the released sample can
contaminate the exterior of the capillary tube 10 and inhibit
accurate analysis. Similarly, a misplaced tube label or debris
deposited on the exterior of the capillary tube 10 during handling
can also inhibit or prevent accurate analysis. In these instances,
the ability of the present device 28 to produce a single
substantially complete image of the centrifuged sample will enable
the operator to identify such potential problems and take
appropriate action. As another example, the image available with
the present device 28 will also enable the operator to evaluate
other aspects of the sample image for potential problems; e.g.,
overall image quality, accuracy of sample coloration, the degree to
which a blood sample may be lipemic or icteric, etc. In those
applications where the operator evaluates the image after
processing and boundary markings are assigned by the processor 36,
the operator can evaluate whether the assigned boundary markings
are accurately positioned relative to the sample image. Hence, the
ability to have an operator visually evaluate an image using the
present device 28 provides considerable quality controls to the
analysis process. It should be emphasized that the present
instrument, as described herein, may be used in locations where
trained operators are present, and also locations where no trained
operators are present (e.g., a CLIA-waived environment). In the
latter type location, the sample images captured by the present
device 28 may be sent to a remotely located trained operator for
analysis. If it is not possible to have a trained operator review
the image and/or results within a predetermined period of time, the
present device 28 may be programmed to prevent the release of any
data if the sample image has any detectable anomalies. A visual
image analysis is preferable in that the criteria for analysis
rejection can be loosened, but a purely automated analysis (e.g.,
that checks for anomalies) is preferable to no analysis at all.
[0025] The extent to which the present device 28 images the
centrifuged sample within the tube 10 makes possible another
quality control mechanism. As indicated above, the present device
28 images substantially all of the radial width 18 and a
significant portion of the axial length of the centrifuged sample.
In some instances, the radial portion of the image can be expanded
to a point outside of the capillary tube 10 to include other
imageable features such as calibration markers or areas. The image
characteristics associated with the regions outside of the
capillary tube 10 can be compared against the characteristics of
the region inside the tube 10. Inconsistencies identified by the
comparison of the characteristics (e.g., brightness) can be used to
evaluate the accuracy of the image. This type of quality control is
not possible using the prior art reading devices that utilize a
linear scanning device, which has essentially only a one pixel
width.
[0026] Although the invention has been described and illustrated
with respect to exemplary embodiments thereof, the foregoing and
various other additions and omissions may be made therein and
thereto without departing from the spirit and scope of the present
invention.
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