4007. Faecal occult blood test
Description
A test for occult blood can detect altered hemoglobin in red blood cells, even if the red blood cells themselves are not detected during a microscopic examination of stool.
Detection of human hemoglobin in stool is a highly specific test for the diagnosis of bleeding from the lower gastrointestinal tract, since the blood entering the intestinal lumen is subject to little destruction. Since hemoglobin in feces is an unstable analyte, false-negative results may be obtained when diagnosing bleeding in the small and upper parts of the large intestine.
Parallel determination of transferrin in feces makes it possible to detect bleeding in the upper gastrointestinal tract with a high degree of reliability. Detection of fecal transferrin is typical for bleeding from the upper and lower (in case of significant damage to the mucous membrane) parts of the gastrointestinal tract.
This test determines the presence of occult blood in the stool without indicating the levels of hemoglobin and transferrin.
When and who needs the test?
- non-invasive diagnosis of latent gastrointestinal bleeding, selection of patients for endoscopic examination;
- early screening testing for colorectal cancer;
- diagnosis of gastrointestinal diseases (intestinal polyposis, diverticulitis, ulcerative colitis, necrotizing enterocolitis in young children, etc.);
- an approximate determination of the level of bleeding (upper or lower gastrointestinal tract);
- differential diagnosis of anemias;
- preventive examinations after 50 years;
- upon detection of helminths – to assess damage to the mucous membranes of the gastrointestinal tract;
- assessment of the adequacy of therapy for gastric ulcer, ulcerative colitis, Crohn's disease, intestinal tuberculosis, etc.
Biological material
- Stool
Preparing for stool testing
- Feces cannot be sent for testing after an enema, insertion of suppositories, or intake of castor or Vaseline oil.
- According to the indications, the doctor prescribes a trial diet, which the patient follows for 4-5 days.
- The stool for testing should not contain any foreign impurities, such as urine.
- For...