Fecal occult blood testing.

Colorectal cancer (CRC) is the third most common cancer in the United States. A reduction in cumulative mortality occurs when patients are routinely screened by fecal occult blood tests (FOBT) and early lesions are removed. These point-of-care tests detect minute amounts of blood released from precancerous and cancerous colon lesions. Positive test results should be followed up with complete diagnostic testing to treat precancerous lesions and diagnose patients at earlier stages of cancer, thereby increasing overall survival. More complex assays are designed to detect genetic changes in cells released from malignant and even premalignant lesions. This article provides information on the screening and diagnostic tests available for CRC detection as well as the advantages and disadvantages of each.