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| Example of Results |
| Test
Card Description and Instructions There are two windows on each test card to which a stool or gastric specimen can be applied. Attached to each card there is a liquid-containing pouch which is released by pulling the tab. After the tab is pulled, you will see a "+" control on the edge of each test card which must turn blue indicating the test has functioned correctly. A blue color in the window test areas is a positive result. No blue in the test areas means no blood was detected. 1. Open the front cover of one Hemaprompt card and using the applicator spread a very thin smear of the specimen on one of the windows. When testing feces, from a different area of the stool, spread a second specimen thinly on the second window. Close the card cover.
2.
After closing the card cover turn to the back of the card. Grip with the
left thumb and finger at the point indicated and hold the foil tab with
the right thumb and finger. Alternatively lay the closed card face down
flat on a table and hold in place with your left thumb at the indicated
grip point. Slowly and steadily pull the foil tab all the way out to the
right and off. Wait one minute after pulling the tab before reading the
test result.
3. Check that the "+" indicator marked "control" has turned blue. If it has not turned blue the test card is faulty and should be discarded. After one minute, inspect the indicated window test areas. Any shade of blue no matter if it is faint or a small speck in either one of the test areas is a positive reaction and indicates that blood is present. Do not read after 3 minutes as the blue color may fade. After noting the results, discard (do not flush) the card and applicator safely. See Examples of Results page for colored illustrations of results you might expect to see. |
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Principle |
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Reagents  Guaiac impregnated paper and developing solution are both mounted on each slide, as is the positive control. The developing solution, a mixture of 60-70% denatured ethyl alcohol and approximately 6% hydrogen peroxide, is contained within a developing pad and is exposed after pulling the tab. The positive monitor contains a hematoid. The specimen can be applied directly by the gloved finger, toilet paper or a spatula. There are 50 slides in each box (Catalogue Number HP50 ). Important Note: Current U.S. Postal Regulations prohibit mailing completed test slides in standard envelopes. ^ top of page |
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Storage Each slide is equipped with a control to monitor the effectiveness of the chemicals and hence the test itself; the positive control must turn blue to indicate a properly functioning test. Failure of this control to produce the appropriate color reactions is indicative of product deterioration and the test results are invalid. HemaPrompt slides should be store at room temperature (15-30C) and should be protected from heat, sunlight, fluorescent light, U.V. radiation, humidity, volatile chemicals and gases. Do not refrigerate or freeze. They are stable until the expiration date indicated on each slide, after which time the slide should not be used. ^ top of page |
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Precautions A special diet as described below is recommended to decrease the possibility of false positive results. On the other hand, dispensing with such a diet for initial screening purpose may increase patient compliance but a positive result under these circumstances would indicate the need to repeat the test in which a special diet two days prior to and during the three day test period is followed. This diet should EXCLUDE red and rare meats, horseradish, raw fruits and vegetables like broccoli, cauliflower, red radish, cantaloupe, parsnips and turnips, or other high peroxidase containing vegetables, which can cause false positive results. An acceptable diet could include cooked fruit and vegetable such as spinach and corn as well as lettuce, prunes, grapes, and apples. Cereal, and well cooked fish and fowl are also acceptable. If any of the recommended foods are known to cause discomfort, the patient should consult his or her physician. Because gastro-intestinal lesions may bleed intermittently and blood in feces is not distributed uniformly all patients who test positive regardless of diet should be followed up with additional diagnostic procedures. Certain medications such as aspirin, [3] indomethacin, phenylbutazone, reserpine, corticosteroids and nonsteroidal anti-inflammatory drugs can cause gastro-intestinal bleeding and thus give positive reactions; dosages of greater than 250mg. of Vitamin C per day have been shown to cause false negative results [4], while iron containing compounds have been mentioned as a cause of false positive reactions [5]. On the advice of the physician, these medications might be temporarily discontinued for 7 days prior to and during the test period. ^ top of page |
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Patient Preparations A special diet as described below is recommended to decrease the possibility of false positive results. On the other hand, dispensing with such a diet for initial screening purpose may increase patient compliance but a positive result under these circumstances would indicate the need to repeat the test in which a special diet two days prior to and during the three day test period is followed. This diet should EXCLUDE red and rare meats, horseradish, raw fruits and vegetables like broccoli, cauliflower, red radish, cantaloupe, parsnips and turnips, or other high peroxidase containing vegetables, which can cause false positive results. An acceptable diet could include cooked fruit and vegetable such as spinach and corn as well as lettuce, prunes, grapes, and apples. Cereal, and well cooked fish and fowl are also acceptable. If any of the recommended foods are known to cause discomfort, the patient should consult his or her physician. Because gastro-intestinal lesions may bleed intermittently and blood in feces is not distributed uniformly all patients who test positive regardless of diet should be followed up with additional diagnostic procedures. Certain medications such as aspirin, [3] indomethacin, phenylbutazone, reserpine, corticosteroids and nonsteroidal anti-inflammatory drugs can cause gastro-intestinal bleeding and thus give positive reactions; dosages of greater than 250mg. of Vitamin C per day have been shown to cause false negative results [4], while iron containing compounds have been mentioned as a cause of false positive reactions [5]. On the advice of the physician, these medications might be temporarily discontinued for 7 days prior to and during the test period. ^ top of page |
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Specimen Collection Stool samples should not be collected if the patient is experiencing menstrual bleeding, constipation bleeding, bleeding hemorrhoids, or when rectal suppositories or medication is being used. It is recommended that smears be collected from two different areas of each stool from three consecutive bowel movements as closely spaced in time as possible, [6][7], or by the physician following a rectal exam. Using toilet paper, gloved finger or spatula, a specimen is taken from stool smeared on the bowl and above the toilet water level, from the toilet paper used following defecation, or from a specimen caught in a clean cup. Application to the slide may be performed from the gloved finger (as after a rectal exam), spatula, or by use of the toilet paper described above. It is important that the stool specimen is applied as a very thin smear to each of the slide windows and that no more than 6 days should elapse between preparation and testing, with patients being instructed to return all slides to the physician as soon as possible. Rehydration of the specimen is not necessary nor recommended. Patient specimens and all materials that come in contact with them, should be handled as potentially infectious and disposed of with proper precaution. Do not allow contact with skin or mucous membranes. ^ top of page |
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Interpretation of Results After pulling the tab out to its limit, results are to be read from the reverse side of the card and through the clear plastic window. ANY trace of blue coloration is to be regarded as a positive for occult blood. An absence of blue indicates no detectable occult blood. These results should be read at room temperature (16-32C) after 60 seconds and before 3 minutes of pulling the tab. Within this time period, the proper functioning of the reagents is indicated by the positive monitor turning blue: Should the monitor reaction be different, the test results are invalid. Contact Aerscher at 800-474-4072 for assistance if an invalid test result occurs. Color blind persons should not interpret the results. Neither the intensity nor the shade of blue from the positive performance monitor should be used as a reference for the appearance of positive test results. ^ top of page |
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Limitations Gastro-intestinal cancers, adenomas and ulcerations do not always bleed. Results cannot be considered conclusive evidence of the presence or absence of GI bleeding or pathology, and false positive/negative reactions are known to occur under certain circumstances such as a person's diet and medications (see Patient Preparation above). The test is not intended as a replacement for other diagnostic procedures and further testing and examination by the physician such as sigmoidoscopy, barium enema, and x-ray studies , need to be performed to determine the exact cause and source of the occult blood in the stool. ^ top of page |
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Expected Results The use of guaiac impregnated paper for the detection of fecal occult blood has been extensively studied and these clinical studies indicate that guaiac impregnated slide tests yield a positive result 3-5% of the time in screening programs and the percent of false positive results lies in the range of 1-2% of persons on a controlled diet [8][9][10] , with the normal daily fecal blood loss in an adult lying in the range of 1-2 mls. of blood per 100 gram of stool [11]. Sensitivity(% of subjects with the condition being sought who test positive) is difficult to estimate, but in series of patients with known colorectal cancer, 50-87% have been reported to yield positive reactions[12][13][14] Estimates of positive reactions with adenomatous bleeding have varied widely, and appear dependant to a degree on the size of polyp, with polyps less than 2 cms yielding less than 5% positive reactions.[15]. ^ top of page |
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Characteristics Hemoglobin was diluted with distilled water to the following concentrations: 1mg/ml, 2mg/ml, 4mg/ml, and 6mg/ml, equivalent to 0.1, 0.2, 0.4, and 0.6 grams hemoglobin per 100 grams of stool respectively, and approximately 1,2,4 and 6 ml. of blood per 100 grams of stool. These dilutions were used to test the sensitivity of HemaPrompt as well as to compare the reactions of several other commercially available guaiac slide tests concurrently with HemaPrompt. In testing, HemaPrompt reacted positively at hemoglobin concentrations of 4mg/ml or greater, in less than 1 minute. At 2mg/ml, HemaPrompt gave a positive reaction in less than 3 minutes when a lesser degree of blue was evident. Below 2mg/ml no positive reactions were observed. Furthermore all positive monitors reacted in the expected manner (+ve turned blue). Exposing the guaiac paper to UV light for ten minutes inactivated the expected reaction. It was concluded that HemaPrompt reacted positively to all hemoglobin levels above 2mg/ml, at which level several other commercially available guaiac slide tests reacted comparatively and similarly to HemaPrompt [16]. ^ top of page |
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Example of Results
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