See Fecal occult blood testing
Fecal immunotesting most often refers to the fecal immunochemical test (FIT), which is a non-invasive screening method for colorectal cancer that detects occult blood in stool using antibodies specific to human hemoglobin.
The FIT test is primarily used for colorectal cancer screening, aiming to detect cancers and precancerous lesions such as polyps at an early, more treatable stage.
It is recommended as a regular annual screening for adults starting at age 45, though earlier testing may be advised for those at higher risk.
The FIT detects human hemoglobin using antibodies, making it specific for blood from the lower intestines (colon and rectum).
It is not affected by diet or most medications, meaning pre-test restrictions are mostly unnecessary.
A stool sample is collected and mailed or delivered to a laboratory for analysis.
The sample is sent to a lab, which analyzes it for hemoglobin using immunochemical methods.
FIT is more specific and sensitive than older guaiac-based fecal occult blood tests (gFOBT), reducing false positives.
It is convenien process as the sample collection is done at home, and no dietary restrictions are needed.
The FIT cannot pinpoint the exact source of bleedin and additional evaluation is required when the result is positive.
It primarily detects bleeding from the lower GI tract, not the upper GI tract[1].
Fecal immunotesting via FIT is an effective, non-invasive way to screen for colorectal cancer and should be repeated annually as part of routine health maintenance.