What does a positive fecal occult blood test mean

A positive fecal occult blood test generally refers to occult blood in the stool, or a small amount of bleeding in the digestive tract. At this time, the symptoms are generally not found through appearance, and blood in the stool can only be observed in laboratory test data. Such test results are of great clinical significance. It may be caused by digestive tract diseases or some anorectal diseases.

Clinical significance

1. Bleeding in the upper gastrointestinal tract: OB is positive

2 Peptic ulcer: The positive rate is 40%~70%, which is intermittently positive. When the stool appearance is normal after treatment, OB can still be positive for 5~7 days. After that, if the bleeding stops, OB can turn negative. As long as the gastrointestinal bleeding is greater than 5ml, it can be positive, but it is not a direct basis for diagnosis. If OB is strongly positive, it indicates peptic ulcer with bleeding.

3. Digestive tract cancer: The positive rate is 95%, and it is continuously positive. OB can be used as a screening indicator for digestive tract cancer.

4. Epidemic hemorrhagic fever: positive rate 84%, OB is an important evidence

5. Drugs cause gastric mucosal damage (eg aspirin, indomethacin, glucocorticoids, etc.), intestinal tuberculosis, ulcerative conjunctivitis, colon polyps, hookworm disease, etc., OB shows positive.

Precautions

1. The stool specimen should be picked from the center of the stool mass, and it should not be mixed with bleeding from the anus or rectum. The stool should be fresh. To increase the chance of detecting blood in the stool, stool samples can be collected multiple times.

2.3% hydrogen peroxide must be effective. A positive control test should also be done. Apply hydrogen peroxide on the blood smear. If there is foam, it can be used.

3 Do not consume animal blood, meat, liver, iron supplements (ferrous sulfate, ferrous citrate, red supplement pills, iron fumarate), or foods rich in chlorophyll (spinach, green vegetables) within 3 days before the test to avoid false positive reactions; do not take large amounts of vitamin C or other reducing substances to avoid false negative reactions.

4 Bleeding gums, nosebleeds and menstrual blood can also cause a positive reaction.

5. Utensils should be sterilized.

Fecal occult blood test is also called fecal occult blood test. It is a test used to check for hidden red blood cells or hemoglobin and transferrin in the stool. This is a very useful diagnostic indicator for checking gastrointestinal bleeding.