Tests for occult blood in stools

Article written by Nguyen Thi Thuy Hang - Doctor of Microbiology - Laboratory Department - Vinmec Times City International General Hospital.

Currently, Vinmec Times City International General Hospital is applying two types of hidden blood tests in qualitative stools and hidden blood in quantitative stools.

There are 2 main methods of testing for fecal occult blood used in the laboratory including:
Guaiac fecal occult blood test (gFOBT): This test requires the patient to take 2 -3 stool samples and must change diet, medication (stop non-steroidal anti-inflammatory drugs 7 days before sampling; avoid broccoli, radish, red meat, vitamin C dose above 250 mg/1 day in 3 days). Immunochemical FOBT or Faecal immunochemical tests (FIT): This test is more commonly used because of its advantages over gFOBT because of its higher sensitivity. It does not require any dietary restrictions prior to sample collection and can be performed on a random stool sample.

Currently, Vinmec Times City International Hospital uses 2 types of tests to find hidden blood (also known as hidden red blood cells) in the stool. Both types have principles based on immunoassay methods:
Qualitative test (rapid test): only shows whether or not occult blood is present in the stool with a threshold of 25 ng/dl. This test does not show how much hemoglobin a person has in the stool. If the test is positive, additional colonoscopy should be performed. Quantitative test (performed on OC-sensor pledia-Japan machine): gives an estimate of human hemoglobin concentration in stool to give instructions for colonoscopy indication: hemoglobin 100-200 ng/ml: indication for colonoscopy. In this case, the specificity of the test for detecting lower gastrointestinal bleeding due to colorectal cancer was up to 97%. Hemoglobin <100 ng/dl: no indication for colonoscopy Vinmec International General Hospital is one of the hospitals that not only ensures professional quality with a team of leading medical doctors, equipment system modern technology but also outstanding with comprehensive and professional medical examination, consultation and treatment services; civilized, polite, safe and sterile medical examination and treatment space. Customers when choosing to perform tests here can be completely assured of the accuracy of test results.