Fecal Occult Blood Test (FOBT)

Fecal Occult Blood Test (FOBT)

Fecal Occult Blood Test (FOBT) is a test used for detecting the presence of hidden (occult) blood in the feces, which may be a sign of certain diseases such as cancer. Fecal occult blood means tiny amounts of blood that can only be detected by certain medical tests. FOBT can detect the presence of multiple diseases, giving healthcare practitioners a useful initial screening tool for many gastrointestinal disorders.

Preparation

Patients should not eat or drink anything for 8-12 hours before the test. Some medications interfere with the results, so patients should let their healthcare practitioner know about any medications they are taking prior to the test. Additionally, some foods, such as red meat, can give false results. As such, patients should inform their healthcare practitioners about any dietary changes they have made recently.

Procedure

The test is usually done at a doctor’s office or a laboratory. During the procedure, a healthcare practitioner will collect a sample of stool and test it for the presence of blood. The test is usually done by looking for an enzyme called heme which is present in red blood cells. If the test detects the enzyme, then it indicates that there is some undetected blood in the sample. The test results are usually available within a few days.

Types of FOBT

There are two main types of FOBT: qualitative and quantitative. Qualitative FOBT detects the presence of blood only. Quantitative FOBT is more sensitive and can measure the amount of blood present in the stool sample.

Risks and Side Effects

The procedure is generally considered safe and there are no known side effects. However, it is important to follow all the instructions provided by the healthcare practitioner.

Why It Is Done

FOBT helps diagnose a number of gastrointestinal disorders, including ulcers, colorectal cancer and diverticulosis. FOBT can also detect blood in the stool caused by certain infections, such as Giardia, and can help to diagnosis the source of the infection.

When It Is Done

It is recommended that adults at average risk for certain conditions undergo FOBT annually or biennially between the ages of 50 and 75. People at higher risk, such as those with a family history of colorectal cancer or certain conditions, should be screened more frequently.