Fecal occult blood test

OBT means that the amount of bleeding in the digestive tract is small, the blood is not visible to the naked eye, and a small amount of red blood cells are digested and decomposed, so that no bleeding can be found under the microscope. At present, the chemical method and the monoclonal antibody method are mainly used.

Basic Information

Specialist classification: Digestive examination classification: feces / parasitic examination

Applicable gender: whether men and women apply fasting: not fasting

Analysis results:

Below normal:

Normal value:

Above normal:

Negative is normal, indicating no bleeding symptoms in the digestive tract.

Positive, indicating gastrointestinal bleeding or ulcer symptoms, common in digestive ulcers or bleeding disorders, as well as systemic diseases such as purpura and hemophilia.

Tips: Vegetarian food should be used for 3 days before the test, and do not eat green leafy vegetables, and banned VitC, iron and other drugs, for 3 days. Normal value


Clinical significance

Abnormal results:

(1) Positive:

1 blood in the stool (lower gastrointestinal bleeding), hepatic fissure, anal fistula, anal or rectal injury, non-specific proctitis, colon and rectal ulcer, rectal tumor, radiation proctitis, acute bacterial dysentery, amoebic dysentery, ulcerative Colitis (chronic non-specific ulcerative colitis), colonic diverticulosis, colon cancer, acute hemorrhagic necrotic enteritis, Crohn's disease (limited enteritis), intussusception, small intestinal hemangioma, and the like.

2 hematemesis and black feces (upper gastrointestinal bleeding) esophageal and gastric varices, gastric ulcer and duodenal ulcer active period, stress ulcers (hemorrhagic gastritis), stomach cancer, pancreatic cancer.

3 systemic disease aplastic anemia, acute leukemia, various types of purpura, hemophilia, malignant histiocytosis (malignant reticulocyte disease), epidemic hemorrhagic fever, typhoid fever, typhus, sepsis, leptospirosis, Schistosomiasis, hookworm disease, regression fever, vitamin C deficiency, vitamin K deficiency, etc.

4 toxic diseases, bacterial food poisoning, drug poisoning (furanylamine, aspirin, chlortetracycline), poisonous plant poisoning (toadstool, cottonseed, Xanthium), chemical poisoning (mercury, arsenic, yellow phosphorus) .

(2) False positives are taken from pig liver, animal blood, spinach, iron, and blood from the respiratory tract or mouth.

Need to check the crowd:

Blood in the stool, hematemesis symptoms.

Positive results may be diseases: pediatric functional dyspepsia, elderly colorectal cancer, rectal injury precautions

Preparation before inspection:

1, should be vegetarian for 3 days before the test, and banned VitC, iron and other drugs, continuous inspection for 3 days.

2, should pick the pus and blood for inspection.

Requirements for inspection:

Avoid collecting the urine and tap water that is in the toilet during collection; do not place the stool directly on toilet paper or paper towels.

Not suitable for people:

There is no inappropriate crowd.

Inspection process

1. Chemical method: Heme in hemoglobin has the activity of peroxidase (PeroXidase, POX), which can decompose peroxide and catalyze the coloration of coloring matter. The shade of color reflects the hemoglobin content, which is the amount of bleeding.

2, immunocolloidal gold (immunological colloidalgold) method: the combination of monoclonal technology and colloidal gold technology, the use of anti-human hemoglobin or anti-human erythrocyte matrix monoclonal antibody, and human hemoglobin or human red blood cells have a highly specific characteristics to detect fecal occult blood.

Not suitable for the crowd

No taboos.

Adverse reactions and risks

This check will not cause complications or harm.