Device for occult blood testing

The device consists of a base sheet of impermeable plastic such as vinyl, or the like, and a guaiac stool receptor sheet adhesively secured thereto. The base sheet is sufficiently larger than the receptor sheet so to form an impermeable skirt which surrounds the receptor sheet so as to form an hermetic barrier protecting the receptor sheet on the underneath one of two of the devices when stacked one on top of the other. A performance/control monitor is included on the device. The monitor includes a peroxidatively active material such as hematin, or the like, which confirms the reactively of the guaiac-impregnated sheet, as well as the activity of the peroxide developing solution. The monitor material is kept out of reactive contact with the guaiac receptor sheet until the developer reagent is applied to the device. A stack of the devices is packed in a sealed container of plastic, or the like, so that the individual devices can be removed from the container one at a time. The devices are designed for use in the physician's office for reception of stool smears taken manually on a rubber glove or finger cot by the physician from patients.

This invention relates to a device for use in testing stool for occult 
blood. More particularly, this invention relates to such a device which is 
inexpensive to produce, which is designed for use by physicians in their 
offices, and which includes a performance/control monitor. 
Many devices have been suggested in the prior art for use in obtaining 
stool samples for analysis for occult blood. Typical of such devices are 
those disclosed in U.S. Pat. Nos. 3,996,006 to Pagano; 4,175,923 to 
Friend; 4,365,970 to Lawrence; 4,259,964 to Levine; and 4,273,741 to 
Levine. 
The above-listed patents all disclose stool sampling devices which are 
designed for use by a patient, generally in the privacy of the home. At 
present, when stool samples are taken in the physician's office by the 
doctor with the use of a rubber glove during a rectal examination, the 
stool is smeared on a sheet of guaiac-impregnated paper and a developer 
reagent is applied to the stool smear to ascertain the presence or absence 
of occult blood in the stool. The guaiac-impregnated sheets presently used 
in the physician's office do not include any performance/control monitor 
which will indicate the reactive state of the guaiac when the developer 
reagent is applied to it. The guaiac reagent used in occult blood testing 
of stool is susceptible to degradation when exposed to air and/or to 
light. The guaiac-impregnated sheets presently used by physicians in their 
offices are permeable to air and are not packaged to ensure shielding from 
light or air circulation. Thus, a stack of such sheets, even when disposed 
in a carton, is subject to exposure to light and/or air and, thus, prone 
to degradation of the guaiac during storage of the sheets. It is apparent 
that a stool sample analyzed on a sheet of degraded guaiac paper, which 
does not have a performance/control monitor associated therewith, can give 
an invalid reading in that no color change will appear even though the 
stool has blood in it. 
The device of this invention is designed for use in the physician's office 
and serves as a receptor of a stool smear applied to it from the 
physician's rubber glove. The sample is taken from the patient by the 
physician inserting the finger of a rubber glove clad hand into the 
patient's rectum. The testing device includes an impermeable base sheet of 
pliant plastic material such as vinyl, or the like. Disposed on the 
impermeable sheet is an absorbant stool receptor sheet of 
guaiac-impregnated paper, or the like. The receptor sheet is sufficiently 
smaller than the base sheet so that a skirt surrounding the receptor sheet 
is formed by the margins of the base sheet. This skirt is impermeable to 
air and moisture. Disposed on the device, as for example on one corner of 
the receptor sheet, is a performance/control monitor formed from hematin 
or some other peroxidatively active reagent which causes a change in color 
when the developer reagent is applied to the monitor and the guaiac sheet. 
The performance/control monitor verifies the condition of the guaiac, as 
well as the developing solution. The monitor reagent is kept out of 
reactive relationship with the guaiac-impregnated sheet until the 
developer reagent is added. This prevents formation of a heme-guaiac 
complex which can form in the prior art devices when the peroxidase 
positive reagent is applied directly to the guaiac sheet. Such heme-guaiac 
complexes as exist in the prior art can give a false indication of a 
properly functioning test system, due to the fact that the heme-guaiac 
complex is more resistant to light and air degradation than the plain 
guaiac paper. 
The devices may be packaged in stacks of about one hundred, and each stack 
is disposed in an air-tight opaque container which is preferably made from 
a relatively rigid plastic material, such as polystyrene or ABS. Inside 
the container is a spring loaded follower which pushes the stack toward 
one end of the container. A slot is formed in the side of the container 
near that one end, the slot providing a port for withdrawing the devices 
one at a time from the container. The container can be secured to a mount 
which is fastened to a wall in the physician's laboratory, or, can be 
provided with suction mounts capable of securing the container to a lab 
bench. The end of the container housing the spring is recessed to provide 
a well for containment of a bottle of the developer reagent. The well also 
serves as a spring guide for the follower spring. 
It is, therefore, an object of this invention to provide a device suitable 
for use in a physician's office by the physician for analyzing stool 
samples for the presence or absence of occult blood. 
It is a further object of this invention to provide a device of the 
character described which includes a performance/control monitor to verify 
the validity of the test results observed. 
It is an additional object of this invention to provide a device of the 
character described wherein the performance/control monitor includes a 
peroxidatively active reagent which is kept out of reactive contact with 
the guaiac-impregnated sheet until the developer reagent is applied to the 
device. 
It is another object of this invention to provide a device of the character 
described which is adapted to be packaged in an air-tight, yet loose, 
stack to protect the guaiac reagent against degradation during storage. 
It is yet another object of this invention to provide a device of the 
character described wherein the devices are dispensed from a stack thereof 
disposed in an opaque container which protects the guaiac reagent from 
exposure to light.

Referring now to the drawings, there is shown in FIGS. 1 and 2 a preferred 
embodiment of a stool testing device denoted generally by the numeral 2, 
which is formed in accordance with this invention. The device 2 includes a 
basal sheet 4 which is formed from a plastic such as vinyl, or a 
plastic-paper laminate, or some other pliant material which is impermeable 
to moisture and air. A guaiac-impregnated stool receptor sheet 6 is 
adhesively secured to the basal sheet 4 and a performance/control monitor 
8 is secured to the receptor sheet 6. The receptor sheet 6 is preferably a 
fibrous paper member, and the monitor 8 includes a base part 10 made from 
paper or some similar material, and a button part 12 which is deposited on 
the base part 10 and which contains the absorbed hematin reactant. The 
base part 10 of the monitor 8 serves to chemically isolate the hematin 
reactant from the guaiac in the receptor sheet 6. Thus, the base part 10 
of the monitor 8 prevents the hematin reactant from combining with the 
guaiac to form a heme-guaiac complex which, as previously noted, could 
provide a false indication that the guaiac in the receptor sheet is still 
viable when the developer reagent is applied to the monitor 8. When the 
developer reagent, such as peroxide, is applied to the button 12, the 
hematin is eluted from the button and the developer and hematin solution 
spill over the edges of the base part 10 onto the guaiac-impregnated 
receptor sheet 6. If the guaiac is still viable, the characteristic blue 
color will appear about the base part 10. FIG. 3 illustrates the manner in 
which the receptor sheet 6 is secured to the basal sheet 4 by adhesive 
areas A and, also, illustrates the manner in which the reagent button 12 
is deposited on the base 10 of the performance/control monitor 8. 
It will be noted from FIG. 2 that the basal sheet 4 extends outwardly 
beyond the edges of the receptor sheet 6 sufficiently to form a protective 
skirt 5 surrounding the receptor sheet 6. A patient identification area 7 
can be provided on the skirt 5, if so desired. 
The device is used as follows. Once the stool sample is obtained by the 
physician, a smear is wiped off the rubber glove onto the receptor sheet 6 
approximately in the center thereof. The developer reagent is then applied 
to the stool smear on the receptor sheet and, also, to the 
performance/control monitor 8. If the characteristic blue color is 
observed about the stool smear and the monitor, then the presence of 
occult blood in the stool is confirmed. If the blue color appears only at 
the monitor 8, then the absence of occult blood in the stool is confirmed. 
If no blue color appears at the monitor location, then the degradation of 
the quaiac and/or the developing solution is confirmed, and a second test 
is made with new reagents. 
Referring now to FIGS. 4 and 5, a second embodiment of the device is shown. 
The second embodiment 3 includes a basal sheet 4 of pliant impermeable 
material, having adhered thereto a smaller stool receptor sheet 6. The 
basal sheet 4 is sufficiently larger than the receptor sheet 6 so as to 
form an impermeable protective skirt 5 surrounding the receptor sheet 6. 
The performance/control monitor 8 is disposed on the basal sheet 4 beneath 
a marginal portion of the receptor sheet 6. The receptor sheet 6 is 
secured to the basal sheet 4 by adhesive areas A, and the monitor 8 
includes the peroxidatively active reagent button 12 which can be 
deposited directly on the basal sheet 4, or can be on a base member as 
previously described, which base member is, in turn, secured to the basal 
sheet 4. The receptor sheet 6 is dry, and the reagent button 12 is also 
dry prior to application of the stool sample and developer reagent. Since 
both of these elements are dry, the peroxidase positive reagent will not 
be in chemically reactive contact with the quaiac until the developer 
solution wets both the receptor sheet 6 and the reagent button 12 and 
causes all of the chemicals to reactively intermingle. Thus, the device, 
while including a performance/control monitor, will not produce a 
heme-quaiac complex during storage prior to use. 
The device is used in the same manner as previously described with the 
exception that the developer reagent is applied to the receptor sheet 6 
over the monitor button 12, whereupon the color change leaches through the 
receptor sheet 6. 
Referring now to FIG. 6, a stack of the devices of FIG. 1 or 4 is shown. 
The stack S is formed so that the devices therein are aligned so as to 
provide relatively uniform margins for the stack. Thus, the receptor 
sheets 6 are disposed generally in vertical alignment, and the skirt 
portions 5 of the basal sheets 4 overlie each other to form the margins of 
the stack S. It will be appreciated that the skirt portions of the 
individual devices overlie each other closely so that when two of the 
devices are disposed atop each other, the impermeable basal sheets 
envelope the receptor sheet on the lowermost of the two devices to protect 
it from air, moisture and light. Thus, in a stack of the devices, each 
receptor sheet except the uppermost one is protected so as to guard 
against degradation of the guaiac. The skirt portions 5 of each basal 
sheet 4 must be extensive enough to thusly protect the receptor sheet 6 on 
the underlying device. 
Referring to FIGS. 10 and 11, an alternative form of the device of this 
invention is shown which is produced in strip form. The strip has a 
continuous web W formed from the impermeable plastic material. The devices 
2 are serially arranged on the strip, with adjacent devices 2 being 
interconnected by flaps 50. Each flap 50 is integral with an associated 
one of the devices 2 and has edges 52 which converge toward a tear line 54 
connecting the flaps 50 with the next adjacent device. The web W is folded 
as shown in FIG. 10 and, thus, packaged in a container as previously 
described. To dispense the devices, one pulls the lead flap 50, its 
attached device 2, and the next flap 50 out of the container. One then 
ruptures the tear line 54 leaving the trailing flap projecting from the 
container for easy grasping when the next device is to be dispensed. 
Referring now to FIG. 7, there is shown a preferred embodiment of a 
container from which the devices can be individually dispensed in the 
physician's office. The container, denoted generally by the numeral 20, 
includes a bottom part 22, and a top part 24 which is snap fitted onto the 
bottom part 22. The two parts are preferably made from injection molded 
plastic, such as polystyrene or ABS. The container 20 has approximately 
the same cross sectional area as the stack of devices previously shown so 
that the stack retains its configuration when placed in the container. A 
dispensing slot 26 is formed at a bottom corner of the container to allow 
individual devices to be drawn from the bottom of the stack and out of the 
container. The slot 26 will initially be closed by a strip of impermeable 
tape, or the like. The top part 24 of the container 20 is formed with a 
well 28 in its upper surface for the reception and storage of a bottle 30 
of the developing reagent. 
Referring to FIG. 8, the interior of the container 20 is shown. The stack S 
of devices is biased downwardly in the container 20 by a follower 32 
which, in turn, is biased by a follower spring 34. The spring 34 is a coil 
spring which ensleeves the well 28 so that the wall of the well 28 serves 
as a spring guide for the follower spring 34. The follower 32 will 
preferably be formed from an impermeable material so as to protect the 
receptor sheet on the topmost device in the stack S. It will be noted that 
the developer reagent bottle 30 preferably fits completely within the well 
28 so that the entire package can be shrink-wrapped for shipment to 
physicians' offices. The bottom of the container 20 may be provided with 
profiled projections 36 integral with the remainder of the container which 
are adapted to have rubber suction cups 38 (shown in phantom) secured 
thereto. The suction cups 38 adapt the container for securement to the top 
of a lab bench, or the like. 
Alternatively, the back wall of the container 20 may be formed with an 
integral rib 40 which is profiled so as to be removably slidably 
insertable into a mating slot formed in a mounting piece which can be 
fastened to a wall in the physician's office. 
It will be readily appreciated that the device of this invention is 
inexpensive to produce and yet dependable in operation. The provision of a 
performance/control monitor on the device which is not in a chemically 
reactive relationship with the receptor sheet until the developer reagent 
is added to the device ensures proper operation of the monitor. The 
developer reagent wets the peroxidatively active monitor reagent and the 
guaiac and allows both to combine in the chemical reaction which results 
in the characteristic color change when the guaiac has not degraded during 
storage. The devices are formed so that the guaiac impregnated receptor 
sheets will be protected against air, moisture, and light when the devices 
are disposed in a stack. The stacks are packaged in opaque containers 
which have means for spring loading the stack so that individual ones of 
the devices can be drawn from the container from the bottom of the stack. 
The container has a well in its top wall which serves as a spring guide 
for the spring loading means and also houses a bottle of developer 
reactant used in the testing. 
Since many changes and variations of the disclosed embodiments of the 
invention may be made without departing from the inventive concept, it is 
not intended to limit the invention otherwise than as required by the 
appended claims.