Stool-based screening remains a cornerstone of colorectal cancer prevention, with randomized trials showing that screening can reduce CRC incidence by up to 18% and mortality by up to 33%. In the U.S., the most commonly used noninvasive stool tests include the fecal immunochemical test (FIT) and multitarget stool DNA testing (mt-sDNA), both recommended starting at age 45 for average-risk individuals.
FIT detects human hemoglobin in stool and has largely replaced guaiac-based tests due to its higher sensitivity and specificity for CRC and advanced adenomas. In contrast, mt-sDNA testing (e.g., Cologuard) combines FIT with molecular biomarkers associated with colorectal neoplasia, offering higher sensitivity for cancer detection but at the cost of lower specificity and the need for full-stool sample collection and centralized lab processing.
Recent advances in stool testing aim to improve detection of both CRC and advanced adenomas. Second-generation mt-sDNA tests have demonstrated improved performance; for instance, the Blue-C study reported sensitivity of 94% for CRC and 43% for advanced adenomas, with specificity of 93%. Expanding access to these noninvasive screening options may improve patient adherence and overall screening uptake.