Written by Lisa Smith, MLS (ASCP) CM, API Technical Specialist
In recognition of Movember and men’s health issues, American Proficiency Institute (API) would like to turn the spotlight on fecal occult blood (FOB) testing. Fecal occult blood testing is a non-invasive, inexpensive screening tool that can aid in the early detection of colorectal cancer. According to the American Cancer Society (ACS) website, colorectal cancer is more common in men; their lifetime risk of developing colorectal cancer is 1 in 23. The ACS estimates approximately 81,540 new cases of colorectal cancers in men in the United States during 2024. Read on to find out more about FOB screening tests and the role that proficiency testing, also called external quality assessment, plays in ensuring accurate results.
Testing for fecal occult blood is often done by a simple screening test that detects occult, or “hidden,” blood from a patient’s stool sample. Although it is not a cancer diagnosis, occult blood in the stool may be a sign of colorectal cancer. If a fecal occult blood test is found to be positive it is typically followed up by a colonoscopy to detect the source of the bleeding.
The fecal occult blood test (FOBT), also referred to as a hemoccult test, is performed by smearing stool on one side of a paper card that is impregnated with guaiac. Guaiac is a resin that comes from the guaiacum tree and is used to test for traces of blood. A small amount of developer solution is then added to the opposite side of the card. If there are traces of blood present a color change will occur.
Another type of fecal occult blood screening is the Fecal Immunochemical Test (FIT) which utilizes an antigen-antibody method to detect hemoglobin in stool. Stool is collected in a tube that contains extraction buffer and this sample is applied to a lateral flow immunoassay cassette, which is similar to a home pregnancy test. After application of the sample an internal control line should appear. If a secondary line appears as well, it indicates the sample is positive for hemoglobin.
Even though fecal occult blood testing seems simple to perform, it can sometimes be tricky. It is easy for an inexperienced technologist to put too much stool on the card making the result difficult to read, or for a technologist to have trouble determining if there has been a true color change. Proficiency testing helps to ensure that the personnel performing and reading the test are consistently achieving the correct results. Proficiency testing also helps to ensure that the kits, reagents, and procedures used to perform FOB testing are working as expected.
API offers a fecal occult blood program consisting of simulated stool samples that are compatible with either guaiac or immunoassay testing methods. For assistance with employee training and education, an FOB competency program is also available. As of July 2024, over 5,300 laboratories were enrolled in API’s fecal occult blood programs. Overall laboratories have excellent performance, with an average of 99% obtaining correct results, demonstrating that laboratories are providing reliable and accurate results for FOB screenings.
API also offers several other proficiency programs relevant to men’s health including testicular and prostate cancer markers, testosterone, and sex hormone binding globulin (SHBG).
Join the 5,300 laboratories already enrolled in API’s fecal occult blood program. Ensure your laboratory is equipped with the skills and confidence to deliver accurate, reliable results in FOB testing. Contact CustomerService@api-pt.com to enroll.