Stool For Occult Blood

The method of collection and testing depends on the test procedure used and can vary from laboratory to laboratory. For the guaiac-based test, the laboratory will provide three test cards. Separate stool samples are collected on three consecutive days and for each test, a stool sample should be collected into a clean container and should not be contaminated with urine or water. A test card is labeled with the person's name and the date. A thin smear of stool is put onto a designated area on the card and allowed to dry. Once it is dry, it is stable for several weeks at room temperature. When all the consecutive samples have been collected and dried, the test cards are returned to the health practitioner or laboratory, usually by mailing them. With the OTC flushable reagent pad/tissue method, a test pad/tissue is placed in the toilet after a bowel movement. The pad contains a chemical that produces a color change when blood is present. The person doing the test watches for the characteristic color change and records the findings on a report form. Like the gFOBT, this test is usually done on three consecutive days and then the completed form is returned to the health practitioner. The use of toilet bowl cleansers or the presence of blood-derived from urine or a woman's menstrual period may alter results. With the fecal immunochemical tests (FIT), a common approach is to use a special long-handled brush or any other device in order to collect a sample from the surface of a stool sample. The brush or device is then used to transfer the sample to a special collection card. After the card is allowed to dry, it is returned to the laboratory for further analyses.

Inform the doctor about the medications you may be taking. No other specific preparations are usually required before this test.