A Practical Overview of the Stool DNA Test for Colorectal Cancer Screening

The multitarget stool DNA test with fecal immunochemical test (sDNA-FIT) is recommended by all major US guidelines as an option for colorectal cancer screening. It is approved by the Food and Drug Administration for use in average-risk individuals aged 45 years and older. The sDNA-FIT tests for 11 biomarkers, including point mutations in KRAS, aberrant methylation in NDRG4 and BMP3, and human hemoglobin. Patients collect a stool sample at home, send it to the manufacturer's laboratory within 1 day, and the result is reported in approximately 2 weeks. Compared with FIT, sDNA-FIT has higher sensitivity but lower specificity for colorectal cancer, which translates to a higher false-positive rate. A unique feature of sDNA-FIT is the manufacturer's comprehensive patient navigation system, which operates 24 hours a day and provides active outreach for patient education and reminders in the first month after a test is ordered. Retesting is recommended every 1–3 years, although the optimal testing interval has not yet been determined empirically. The cost of sDNA-FIT is $681 without insurance, but Medicare and most private insurers cover it with no copay or deductible.