Stool deoxyribonucleic acid (DNA) testing is a noninvasive colorectal cancer (CRC) screening test that analyzes stool samples for human DNA shed from colonic epithelial cells, specifically targeting genetic and epigenetic alterations associated with neoplastic lesions.
The most widely used form is the multitarget stool DNA (mt-sDNA) test, which detects molecular markers such as mutant KRAS, methylated BMP3 and NDRG4 promoter regions, and includes a fecal immunochemical test (FIT) for human hemoglobin.
These markers are in association with colorectal adenomas, serrated polyps, and carcinomas, which exfoliate altered cells into the stool.
The mt-sDNA test is FDA-approved for average-risk adults aged 45–85 years and is recommended as an option for colorectal cancerscreening.
Compared to FIT alone, mt-sDNA demonstrates higher sensitivity for CRC (approximately 92–94%) and advanced adenomas (about 42–43%), but lower specificity (86–90%).
The test is typically performed at 3-year intervals.
A positive stool DNA test requires follow-up diagnostic colonoscopy.
The test is not recommended for high-risk populations or for surveillance after polyp removal.
Its main advantage is increased sensitivity for detecting both CRC and advanced precancerous lesions, including sessile serrated polyps, compared to FIT.