Note: Descriptions are shown in the official language in which they were submitted.
CA 02515001 2014-08-22
METHOD AND APPARATUS FOR PROCESSING ASSAY TEST RESULTS
Field of the Invention
The present invention relates in general to a method and apparatus for
processing assay test results. It more particularly relates to a method and
apparatus for
assay tests, such as tests of urine samples for pregnancy, drugs of abuse,
tobacco, or
other.
Background Art
There is no admission that the background art disclosed in this section
legally
constitutes prior art.
Assay tests have been employed to analyze test samples such as urine samples
to determine whether or not they contain substances such as HCG indicating
pregnancy, drugs of abuse, or other.
Reference may be made to the following United States patents:
PATENT NO. INVENTOR ISSUE DATE
4,033,723 Givner, et al. 07-05-1977
4,123,509 Banik, et al. 10-31-1978
4,348,207 Cappel 09-07-1982
4,450,239 Chatterton 05-22-1984
4,700,711 Carlson 10-20-1987
5,182,216 Clayton, et al. 01-29-1993
5,580,794 Allen, et al. 12-3-1996 .
5,656,503 May, et al. 08-12-1997 _
5,786,220 Pronovost, et al. 07-28-1998
5,873,546 Allen, et al. 11-17-1998
6,063,026 Schauss, et al. 05-16-2000 -
6,150,178 Cesarczyk, et al. 11-21-2000
6,235,24161 Catt, et al. 05-22-
2001
Test strips, as disclosed in one or more of the foregoing patents, are
employed to
receive a test sample such as a urine sample for performing an assay test. For
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example, a pregnancy test strip has been used to collect a urine sample to
react with a
reagent to produce a visible line such as a line having a pink/purple color.
It is
sometimes difficult to make a subjective, determination as to
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the intensity of the color of the line relative to a comparison line. Thus,
false
positive indications are sometimes possible.
In an attempt to help interpret the results of such assay test, the U.S.
patent
6,235,241 B1 discloses a test strip disposed within a casing or housing, and
uses
a method of illuminating using diffusers through a test strip to help the user
to
interpret the results of a test. Light is sensed on the other side of the test
strip by
detecting light shining through the test strip. However, such a method is
complex
in its use, and thus relatively expensive to use.
For the purpose of providing a relatively inexpensive assay test device,
which can be for single use only, as disclosed in U.S. patents 5,580,794 and
5,873,546, there is disclosed a method using a test membrane containing a
reagent, and receiving a liquid test sample thereon. The presence of movement
of
the sample liquid is detected and activates the device electrically. The
results of
the chemical reaction of the reagent with the test sample is then sensed. In
this
regard, as the liquid sample moves along the test strip, the reaction is
occurring
and the results are sensed once the liquid reaches a certain point along the
strip.
Alternatively, another method it disclosed where the device may be activated
electrically by closing a switch when it is removed from its pouch, and the
reaction
results are sensed after a specified time.
However, when the former method is used, the reaction time may be
dependent on the length of time it take for the movement of the liquid sample
along the membrane. Thus, the reaction time may not be precisely controlled
and
repeatable, and thus accuracy may be adversely affected.
When the latter method of sensing the reaction results sometime after
initially turning on the device, following a time delay, the reaction time is
even less
precisely controlled. There is little or no control over when the sample is
first
introduced to the membrane following the activation of the device, and thus
the
processing time could vary widely.
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It is, of course, important to provide sufficient time to process the
reaction. Either
permitting the reaction process time to be determined by the propagation time
of the
sample, or by allowing the sample to be introduced at any time (even shortly
before the
reaction is analyzed), does not provide adequate control for the proper
analysis of the
reaction.
Therefore, it would he highly desirable to have a new and improved testing
method, which is relatively more accurate in the determination of the test
results, while
at the same time being relatively inexpensive to use. Thus, such a method may,
if
desired, be employed for a single use, and yet be relatively accurate in its
use.
Summary
In accordance with one embodiment, there is provided a method of testing a
fluid
sample to determine whether or not it contains a certain substance,
comprising: storing,
in at least one storage medium, a predetermined threshold range for readings
of sample
and reaction sensors mounted within a housing, the range indicative of a
desired
amount of light within the housing prior to introduction of the fluid sample;
determining
via the sample sensor an initial sample sensor reading; determining via the
reaction
sensor an initial reaction sensor reading; storing, in the at least one
storage medium,
the initial sample sensor reading and the initial reaction sensor reading;
comparing the
initial sample sensor reading to the predetermined threshold range;
determining, based
on the comparison of the initial sample sensor reading to the predetermined
threshold
range, whether or not the initial sample sensor reading is acceptable;
comparing the
initial reaction sensor reading to the predetermined threshold range;
determining, based
on the comparison of the initial reaction sensor reading to the predetermined
threshold
range, whether or not the initial reaction sensor reading is acceptable;
generating a
signal indicating the test device is faulty if at least one of the initial
sample sensor
reading and the initial sensor reading is not acceptable; flowing the fluid
sample along a
test strip; detecting the presence of the fluid sample via the sample sensor
based on
light reflecting from a first location on the test strip, the sample sensor
spaced from the
test strip; starting a timer configured with a predetermined time delay
interval in
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response to detecting the presence of the fluid sample under test being
received at the
first location on the test strip; generating an electric time-out signal at
the end of the
predetermined time delay interval; using the reaction sensor remote from the
sample
sensor starting the time delay interval for detecting the fluid sample under
test at a
second location on the test strip in response to the time-out signal;
determining whether
or not the fluid sample under test at the second location on the test strip
contains a
predetermined quantity of the certain substance; generating an electric output
signal in
response to the determination of whether or not the fluid sample under test at
the
second location on the test strip contains a predetermined quantity of the
certain
substance; and indicating the presence or absence of a predetermined quantity
of the
certain substance contained within the fluid sample under test, wherein the
sample
sensor and the reaction sensor are photo-optic sensors.
In accordance with another embodiment, there is provided a computer-readable
storage medium including instructions for controlling an apparatus for testing
a fluid
sample to determine whether or not it contains a certain substance, the
instructions
executable by a processor of the apparatus to cause the apparatus to: store a
predetermined threshold range for readings of sample and reaction sensors
mounted
within a housing of the apparatus, the range indicative of a desired amount of
light
within the housing prior to introduction of the fluid sample; determine via
the sample
sensor an initial sample sensor reading; determine via the reaction sensor an
initial
reaction sensor reading; store the initial sample sensor reading and the
initial reaction
sensor reading; compare the initial sample sensor reading to the predetermined
threshold range; determine, based on the comparison of the initial sample
sensor
reading to the predetermined threshold range, whether or not the initial
sample sensor
reading is acceptable; compare the initial reaction sensor reading to the
predetermined
threshold range; determine, based on the comparison of the initial reaction
sensor
reading to the predetermined threshold range, whether or not the initial
reaction sensor
reading is acceptable; generate a signal indicating the test device is faulty
if at least one
of the initial sample sensor reading and the initial sensor reading is not
acceptable; flow
the fluid sample along a test strip; detect the presence of the fluid sample
via the
sample sensor based on light reflecting from a first location on the test
strip, the sample
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sensor spaced from the test strip; start a timer configured with a
predetermined time
delay interval in response to detecting the presence of the fluid sample under
test being
received at the first location on the test strip; generate an electric time-
out signal at the
end of the predetermined time delay interval; start the time delay interval
for detecting
the fluid sample under test at a second location on the test strip in response
to the time-
out signal based on the reaction sensor remote from the sample sensor;
determine
whether or not the fluid sample under test at the second location on the test
strip
contains a predetermined quantity of the certain substance; generate an
electric output
signal in response to the determination of whether or not the fluid sample
under test at
the second location on the test strip contains a predetermined quantity of the
certain
substance; and indicate the presence or absence of a predetermined quantity of
the
certain substance contained within the fluid sample under test, wherein the
sample
sensor and the reaction sensor are photo-optic sensors.
In accordance with another embodiment, there is provided an assay test device
for determining whether a fluid under test contains a certain substance,
comprising: a
housing including a top portion and a bottom portion; and an elongated test
strip
disposed at least partially within said housing, said test strip containing a
reagent, said
test strip including a wick adapted to receive a sample of the fluid under
test at a
sample receiving end portion thereof. The test strip includes: a backing strip
having a
porous carrier strip overlying the upper surface thereof; a fluid absorption
strip at one
end of the backing strip in fluid communication with the porous carrier strip;
a reagent
pad at the opposite end of the backing strip and in fluid communication with
the wick
and the porous carrier strip; and an intermediate portion of the porous
carrier strip
disposed between the spaced apart absorption strip and the reagent pad. The
assay
test device further comprises: an elongated printed circuit board attached to
an inner
surface of the housing extending substantially parallel to the test strip for
mounting
electronic components; a reaction sensor, a light-emitting diode, and a sample
sensor
mounted on one side of the printed circuit board opposite the intermediate
portion of the
porous carrier strip; the sample sensor mounted on said printed circuit board
including a
gap between the sample sensor and said test strip for detecting the presence
of the
sample as it flows from the test strip sample receiving end portion based on
reflectance
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of light from the light-emitting diode at a first position on the test strip
for generating a
signal indicative of the presence of said sample; a processor responsive to
the sample
presence signal for starting a timer to generate a time delay interval and for
generating
a time-out signal at the end of the interval; the reaction sensor mounted on
said printed
circuit board and responsive to said time-out signal for detecting the certain
substance
in the fluid under test received on said test strip based on reflectance of
light from the
light-emitting diode at a second position on the test strip to generate an
electrical signal
indicative of the amount of the substance detected; said processor being
responsive to
said signal from said reaction sensor for generating an output signal
indicative of the
presence or absence of at least a predetermined quantity of the substance
contained in
the sample; and a display mounted on said housing responsive to said output
signal for
indicating the presence or absence of a predetermined quantity of the certain
substance
contained within the fluid under test; wherein the sample sensor is a photo-
optic sensor.
In accordance with another embodiment, there is provided a method of testing a
fluid to determine whether or not it contains a certain substance, comprising:
introducing
the test fluid to the device; optically sensing the presence of the sample of
the fluid
under test at the first portion on the intermediate portion of the test strip;
generating the
signal indicative of the presence of the sensed sample; starting the timer in
response to
the signal indicative of the presence of the sensed sample; generating the
time-out
signal at the end of the time delay interval; optically sensing a reaction in
response to
said time-out signal at the second portion on the intermediate portion of the
test strip;
determining whether or not the fluid under test contains a predetermined
quantity of the
certain substance using the processor; generating the electric output signal
using the
processor in response to its determination; and indicating the presence or
absence of a
predetermined quantity of the certain substance contained within the fluid
under test.
Brief Description of the Drawings
The following is a brief description of the drawings:
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FIG. 1 is a pictorial view of a device which is constructed in accordance with
a
disclosed embodiment of the present invention;
FIG. 2 is an exploded view of the device of FIG. 1;
FIG. 3 is an enlarged sectional elevational view of the device of FIG. 1;
FIG. 4 is an enlarged sectional view of the device of FIG. 3 taken
substantially on
line 4-4 thereof;
FIG. 5 is a fragmentary sectional elevational view of the device of FIG. 3,
illustrating it with its lid portion being removed;
FIG. 6 is an enlarged, sectional view of FIG. 5 taken substantially on line 6-
6
thereof;
FIG. 7 is a schematic circuit diagram of the device of FIG. 1; and
FIGS. 8 and 9 are flow chart diagrams of the software or firmware.
Detailed Description of Certain Embodiments of the Invention
In accordance with certain disclosed embodiments of the present invention,
there is provided an assay test device for determining whether a fluid under
test
contains a certain substance, wherein the device includes a test strip
disposed at least
partially within a housing for receiving the fluid under test. A sensor
mounted on the
housing detects the certain substance in the fluid under test received on the
test strip to
generate an electrical signal indicative of the amount of the substance
detected. A
processor responds to the signal for determining whether or not the fluid
under test
contains a predetermined quantity of the certain substance to generate an
electric
output signal. A display mounted on the housing responds to the output signal
to
indicate the presence or absence of a predetermined quantity of the certain
substance
contained within the fluid under test.
According to other embodiments of the invention, the processor delays in
activating the reaction sensor until after a predetermined time delay
interval. The
processor stores the sensor signal at the completion of the time delay
interval, and
compares the stored sensor signal with stored threshold electric signals to
determine
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whether or not the fluid under test contains a predetermined quantity of the
certain
substance.
According to other embodiments of the invention disclosed herein, the test
strip
includes an elongated wick for receiving the fluid under test at one end
portion of the
test strip. A sample sensor mounted on the housing adjacent to the wick
disposed
remotely of the fluid receiving end portion detects the presence of the fluid
under test to
generate an electric signal indicative of the start of the predetermined time
delay
interval. The test device includes a display element indicating that the
device is ready to
receive the fluid under test. The display also includes a positive substance
indication
display element and a negative substance indication display element.
A lid is removably attached to the housing for covering at least a portion of
the
fluid receiving end portion of the wick so that the lid can be removed from
the housing
to expose the liquid receiving end portion of the wick. A switch activates the
device in
response to the removal of the lid from the housing.
In accordance with certain disclosed embodiments of the present invention,
there is provided a method of testing a fluid sample to determine whether or
not it
contains a certain substance. The disclosed method includes the starting of a
timer in
response to detecting the fluid sample under test being received on a test
strip. The
disclosed method includes causing the generation of an electric time-out
signal
indicative of the end of a predetermined time delay interval. Moreover, the
disclosed
method includes causing the determination of whether or not the fluid sample
under test
contains a predetermined quantity of the certain substance in response to the
time-out
signal. The disclosed method also includes generating an electric output
signal in
response to the determination, and then 'causing the indication of the
presence or
absence of a predetermined quantity of the certain substance contained within
the fluid
sample.
According to other methods of the disclosed embodiments of the invention, the
disclosed embodiments of the methods include monitoring to determine if a
power-up
signal is received to start a test operation.
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Referring now to the drawings, and more particularly to FIGS. 1-6 thereof,
there is
shown an assay test device 10, which is adapted for determining whether a
fluid under test
contains a certain substance, and which may be operated in accordance with a
disclosed
embodiment of the invention. The device 10 includes an elongated housing 12
having a
removable lid or cap 14. The housing 12 is to be held in the hand of the user.
An elongated test strip 16 is disposed longitudinally within the housing 12.
The test
strip may be in the form of the test strip disclosed in the aforementioned
European patent
application No. EP0,962,771A1. The test strip 16 of the device 10 is initially
contemplated
to be used for pregnancy testing, but it is to be understood by those skilled
in the art, that
other different types and kinds of test strips may be employed for other
testing purposes,
including but not limited to, the testing for drugs of abuse, and other tests.
A sample sensor 18 (FIGS. 3 and 5) is mounted on the underside of a printed
circuit
board 19 and is disposed opposite the test strip 16 intermediate its end
portions for
detecting the presence of the sample as it flows along the test strip for
generating a signal
indicative of the presence of the sample. The sample sensor may be a photo-
optic sensor,
but it can be other types and kinds of sensors, including magnetic sensors
such as Hall
effect device.
A processor 21 mounted on the top surface of the printed circuit board 19 is
responsive to the sample presence signal from the sample sensor 18 for
starting a software
timer to generate a time delay interval and for generating a time-out signal
at the end of the
interval. In this regard, the time delay interval allows for the propagation
time of the sample
from one end portion to an intermediate portion of the test strip 16 opposite
the sensor 18.
As shown in FIGS. 3 and 5, a reaction sensor 23 mounted on the underside of
the
printed circuit board 19 responds to the time-out signal from the processor 21
for detecting
a certain substance in the fluid under test received on the test strip 16 to
generate an
electrical signal indicative of the amount of the substance detected. In this
regard, the
reaction sensor is preferably a photo-optic sensor, but it may also be other
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types and kinds of sensors, including magnetic sensors such as Hall effect
devices.
When a photo-optic sensor is used, and when the test strip 16 is employed as
disclosed
in the aforementioned European patent application, a dark line forms on the
test strip
and is detected by the photo-optic reaction sensor 23.
As indicated in FIGS. 1 and 3, a display generally indicated at 25 includes an
amber light emitting diode (LED) 27, a green light emitting diode (LED) 29 and
a red
light emitting diode (LED) 32 disposed in a row on the top surface of the
housing 12,
and are positioned within corresponding holes 34, 36 and 38. The display 25
responds
to an output signal from the processor 21 for indicating the presence or
absence of a
predetermined quantity of the certain substance contained within the fluid
under test.
The processor generates the output signal in response to the signal from the
reaction
sensor 23. The output signal from the processor is indicative of the presence
or
absence of at least a predetermined quantity of the substance contained in the
sample.
A power supply generally indicated at 411s mounted on the top surface of the
printed circuit board 19, and is preferably in the form of a battery 43 which
is connected
electrically to the printed circuit board 19 and its components via a switch
generally
indicated at 45 (FIGS. 4 and 6). A switch actuator 47 preferably in the form
of an
insulator strip 49 extends through an opening 52 in an angular wall portion of
the
housing 12 and extends to the switch 45 when the lid 14 is assembled to the
housing
12 as shown in FIGS. 1 and 3. When the lid 14 is removed from the housing 12
as
indicated in FIG. 5, the actuator 47 is pulled away from the switch 45 as
indicated in
FIGS. 4 and 6, to cause the battery 43 to be connected electrically to the
printed circuit
board 19 for energizing the device 10.
In use, in order to start a testing operation by, for example, testing for HCG
in a
urine sample to indicate whether or not a person is pregnant, the lid 14 is
removed from
the housing 12 to cause the insulation strip 49 to be pulled out from under
the battery
43 to cause the battery to, energize the device 10. Once energized, the device
10
causes the amber LED 27 to blink or otherwise to turn on, indicating that the
power is
on and the device 10 is ready to receive the urine test sample. Should the
device not be
used after being energized, the amber LED 27 blinks or stays on until the
battery
becomes exhausted.
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The user then applies a urine sample to the test strip 16.
The sample sensor 18 detects the presence of the urine sample once it has
migrated along the test strip and the top surface of the test strip turns from
a white color
to a darker color as a result of being wetted by the urine sample. If the
sensor 18 does
not respond to the color change, the device 10 does not proceed further in the
operation and eventually the battery 43 will become exhausted.
The processor 21 causes a software timer to start a time delay interval with
the
actuation of the battery 43 and will stop timing once the sample sensor 18
detects the
presence of the urine sample, or the timer times out. If the timer times out
prior to the
sensing of urine sample, the amber LED 27 will start to blink to provide a
visual
indication that the battery life is near its end.
If the sample sensor 18 detects the presence of the urine sample (even, after
the
amber light commences blinking), the processor 21 responds to an electrical
signal
from the sample sensor 18 to start another time delay interval based on the
performance/optimization of the desired test. In this regard, the time
interval is provided
to allow sufficient time for the test to develop. For example, for a pregnancy
test, there
may be a time-out interval of 3 minutes.
Once the processor 21 reaches the end of the time-out interval, the processor
21
causes the reaction sensor 23 to read the intermediate portion of the test
strip 16 to
detect the presence of a line created by the test reaction. The current value
is
compared with a stored value of the intensity of the line to determine whether
or not the
line is present. If the difference is greater than the defined threshold
level, the green
LED 29 is illuminated, to indicate a positive test result. If the difference
is less than the
threshold value, the red LED 32 is illuminated by the processor, to indicate a
negative
test result. Either the green LED 29 or the red LED 32 remains illuminated
until the
battery dies, or the battery 43 is disconnected from the printed circuit board
19 by
means of the switch actuator 47 engaging the switch 45 by replacing the lid 14
on the
housing 12.
It is to be understood that the device 10 is contemplated to be a single use
device which is relatively accurate in its measurements. However, it will be
understood
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by those skilled in the art that the device 10 may be a multiple use device by
permitting
the test strip to be replaced with a fresh test strip.
Considering now the test strip 16 in greater detail with reference to FIGS. 3
and
of the drawings, the test strip 16 includes a backing strip 54 which has a
sample pad
or wick 56 extends out of the housing 18 and is covered by the lid 14 when it
is
assembled to the housing 12. When the lid 14 is removed from the housing 12,
the wick
56 is exposed so that the urine sample may be applied thereto. A porous
carrier strip 58
has a reagent section or pad 61 affixed to the wick 56, and a fluid absorption
section or
strip 63 at the opposite end portion thereof. A catching section or line
forming zone 65
on the upper surface of the intermediate portion of the porous carrier strip
58 is
disposed opposite the reaction sensor 23 where a line is formed once the
reaction
occurs when human chorionic gonadotropin (HCG) is present in the urine sample,
indicating that the user is pregnant.
The reagent pad 61 contains the suitable reagent for performing the desired
test
on the sample. In this regard, the sample is received on the wick 56 and
migrates
through the reagent pad 61 to the intermediate portion of the carrier strip 58
until the
sample sensor 18 disposed apposite the intermediate portion of the carrier
strip 58
detects the presence of the sample due to the change in color of the wetted
porous
carrier strip 58. In this regard, an illuminating light-emitting diode (LED)
67 disposed on
the underside of the printed circuit board 19 between the sensors 18 and 23
illuminate
the intermediate portion of the porous carrier strip 58 to reflect light
therefrom to the
sensors. The LED 67 may produce light in the visible range of the
electromagnetic
spectrum. A white LID is preferred, but a green LED may also be used for the
illuminating LED 67, depending on the color of the line formed on the test
strip 16.
Thus, in the present example, as a pregnancy test, no control line is
required.
Additionally, the reaction forms a complex produced by bonding between a white
latex
particle and a marking element in the form of colloidal gold to the antigen
HCG.
Considering now the housing 12 in greater detail, the housing 12 includes a
bottom portion 69, which is secured to a top portion 72 for enclosing the
printed circuit
board 19 with its components as well as the test strip 16. When the device 10
is
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employed as a multiple use device, the housing 12 can be disassembled as
indicated in FIG. 2 to permit the test strip 16 to be replaced by a fresh test
strip for
performing additional tests. The insulator strip 49 of the switch actuator 47
may be
in the form of a rigid strip of suitable materials such as thermal plastic or
other
such material. In this regard, the insulator strip 49 can be reinserted
through the
opening 52 and under the battery 43 to disengage it electrically from the
printed
circuit board 19.
Considering now the switch actuator 47 with reference to FIGS. 4 and 6 of
the drawings, the actuator 47 includes a u-shaped spring mounting device 74
which serves as a conductor and surmounts the battery 43 and positions it
opposite to a circuit board negative contact 78. The top portion of the
mounting
device or contact 74 is dimpled at 76 to engage the positive surface of the
battery
43 electrically to provide electrical contact between the positive terminal of
the
battery 43 and a positive terminal 81 on the printed circuit board 19. The
insulator
strip 49 is adapted to be positioned between the negative terminal of the
battery
43 and the circuit board contact 78 as shown in FIG. 4 to disengage
electrically
the battery 43 from the printed circuit board 19. When the lid 14 is removed,
the
insulator strip 49 is fixed at one of its ends to the lid 14 and its opposite
end is
pulled out from between the underside of the battery 43 and the circuit board
contact 78. This causes the battery 43 to have its negative terminal snap into
engagement with the contact 78 due to the spring tension of the spring
mounting
device 74.
Considering now the electrical circuit for the device 10 with reference to
FIG. 7, when the switch 45 is closed by removing the strip 49, the battery 43
is
connected across a capacitor 83, and a parallel combination with the
illuminating
LED 67 connected in series with a current limiting resistor 84 so that the LED
67
becomes illuminated once the switch 45 is closed. This current flow is sensed
by
the processor 21 to cause the amber LED 27 to be energized via a current
limiting
resistor 87. In the actual implementation of the circuit as shown in FIG. 7,
it is
preferred to use a tri-color light-emitting diode (LED) 85 to form the green
and red
colors corresponding to the green LED 29 and the red LED 32 of FIG. 1. The LED
85 is energized via a current limiting resistor 89 by the processor 21.
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The sensors 18 and 23 in the form of photo-optic photo cells are connected via
a
voltage divider network including resistors 92 and 94 to provide the threshold
levels for
the photo cells so that the photo cells will not respond to a change in color
unless it
exceeds the threshold level so that the device 10 can detect a sufficient
amount of the
certain substance contained in the test sample.
The following is a list of components which may be used in connection with the
disclosed embodiment shown in FIG. 7:
S1 1/4 "w X 2" IX 010" H, INSULATION STRIP
Vcc PANASONIC PT #CR1220, LITHIUM COIN BATTERY
KEYSTONE PT #3001, THRU MOLE MOUNT COIN CELL
J2
RETAINER
PCELL1 PERKINELMER PHOTOCONDUCTIVE CELL PT #VT9ONI
R3 4K OHM CARBON FILM RESISTOR, %WATT, 2% AXIAL LEAD
R2 120K OHM CARBON FILM RESISTOR, %WATT, 5% AXIAL LEAD
R1 150 OHM CARBON FILM RESISTOR, 1/4 WATT, 5% AXIAL LEAD
C1 0.1uf CAPACITOR, 50V, 10% CERAMIC, AXIAL LEAD
LUMEX PT #SSL-LX50991GW, 1-5mm (T-1 3/4) RED/GRN
LED2
BICOLOR LED
LED1 LUMEX PT #SSL-LX3044GD, T-3mm (T-1) 565nm GRN LED
J1 DUAL-1N-LINE SOCKET, 8 PIN, OPEN FRAME, TIN LEADS
U1 MICROCHIP PT #PIC2F675-1/P MICROCONTROLLER
Referring now to FIGS. 8 and 9 of the drawings, the method of the disclosed
embodiment of the present invention will now be described in greater detail.
As
indicated at box 96, the powering on of the device 10 will now commence. At
box 98,
the software or firmware for the processor waits for the power up operation to
commence when the insulation strip is removed from the battery by pulling the
lid 14
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from the housing 12. As indicated at box 101, the processor makes a
determination as
to whether or not the powering on of the device 10 is ready. If the closing of
the switch
to the battery has not taken place to produce a power-on signal, the software
continues
to monitor for the power being ready.
Once the lid 14 is removed to cause the power-on signal to. be generated, a
transition is made to box 103, whereby the yellow or amber light emitting
diode is turned
on to illuminate it.
At box 105, a time delay interval commences to allow the light adaptation for
the
photo-cell sensors. As indicated at box 107, the software continues to monitor
the light
adaptation delay. If the delay is not completed, it loops back to continue to
monitor.
Once the light adaptation delay is completed, a transition occurs to box 109
where the photo-cell sensors (the sample sensor and the reaction sensor) are
read to
initialize the system. As indicated at box 112, the information read from the
photo-cell
sensors is stored in the memory of the processor.
As indicated at decision box 114, a determination is made as to whether or not
the photo-cell sensor readings are less than 3,000 ohms. If either one is less
than 3,000
ohms, as indicated at box 116, the amber LED, or if a tri-color LED is used,
all three
colors are illuminated and begin to blink. This blinking light indicates a
faulty reader. For
example, excessive light may be entering the system. Also, there may be a
possible
break in the housing, or a short circuit across a resistor to the illuminator
LED, or other
such problem may exist. In such case, the operation then ends at box 118.
Alternatively, if both of the photo-cell sensor readings are greater than
3,000
ohms, then a decision is made at box 121 as to whether or not the photo-cell
sensor
readings are greater than 10,000 ohms. If they are greater than 10,000 ohms,
then
there may be a faulty reader. In this. regard, either the illumination LED is
not
functioning, or the photo-cell sensors are faulty, or other such problem. As
indicated in
box 123, if at LED is used, the read and green of the tri-color LED are
illuminated. If
individual LED devices are employed, then the red and the green are
illuminated
simultaneously to indicate the end of the operation as indicated at box 125
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Alternatively, if the measurements are less than 10,000 ohms, then the
operation
proceeds to box 127 (FIG. 9). At that decision box, it is determined if
thel3hoto-cell 2
(the sample sensor) is in range or not. If the photo-cell sample sensor fails
to see the
liquid passing by on the test strip, the yellow LED remains on until the
battery dies. If
the photo-cell sample sensor is in range then the operation transitions to box
129 where
the predetermined time delay interval commences to permit the test strip to
develop the
reaction. In the disclosed embodiment, the predetermined time delay interval
is at 3
minutes. A decision box 132 monitors the delay to determine whether or not the
delay
has completed. Once it is completed, the operation transitions to box 134
where the
photo-cell reaction sensor (photo-cell 1) is read.
As indicated at box 135, the reading of the reaction sensor information is
subtracted from the initial reading of the reaction sensor photo-cell, As
indicated at box
137, a determination is made as to whether or not the result is less than the
threshold.
If it is greater than the threshold, then the yellow LED is turned off at box
146 and the
green LED is turned on at box 148 to indicate that a line has been detected at
the test
strip indicating that the reaction has a positive indication, such as an
indication of
pregnancy. The result is greater than the threshold when a reaction line is
present,
because the color of the line is such that there is less reflection of light.
The box 148
then transitions to the end box 144 where the LED remains on until the battery
dies.
Alternatively, if the result is less than or equal to the threshold, then the
transition
from the box 137 is to the box 139 to turn off the yellow LED 139 and turn on
the red
LED 142 indicating that no line has been detected for a negative indication.
When no
dark line is present, then the reflected light is equal to or less than the
threshold
measurement of reflected light. From there, the transition is to the end box
144 where
the red LED remains on until the battery dies.
As will become apparent to those skilled in the art, numerous modifications as
well as variations of the disclosed embodiments of the present invention may
be made
in light of the foregoing teachings. Therefore, it is to be understood that
within the scope
of the appended claims, the invention may be practiced otherwise as
specifically
described herein.
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