David Lieberman, MD1, Theodore R. Levin, MD, MS, FACG2, Samir Gupta, MD3, John M. Carethers, MD, FACG3, Aasma Shaukat, MD, MPH, FACG4, Kimberly Kruse, MSc5, Ryan B. Ghannam, PhD5, Erica K. Barnell, MD, PhD6 1Oregon Health & Science University, Portland, OR; 2Kaiser Permanente Division of Research, Pleasanton, CA; 3University of California San Diego, San Diego, CA; 4NYU Grossman School of Medicine, Division of Gastroenterology and Hepatology, New York, NY; 5Geneoscopy, Saint Louis, MO; 6Washington University School of Medicine in St. Louis, Saint Louis, MO Introduction: Fecal immunochemical tests (FIT) and multi-target stool DNA tests require swabbing stool from a toilet or bucket before mailing the sample to a central lab as part of noninvasive CRC testing. At-home sampling by untrained individuals introduces complexity to stool collection and increases the risk of human error, environmental exposure, and transit-related degradation. Requiring subjects to handle stool is also a potential barrier to adherence. The multi-target stool RNA test (mt-sRNA) is the only test that is FDA-approved for the detection of both CRC and advanced adenomas (AA) that does not require patients to perform an at-home FIT swab. Instead, trained technicians complete the FIT swab in the laboratory after the sample is received. Methods: As part of the CRC-PREVENT clinical trial, subjects produced a stool sample and completed an at-home FIT swab prior to undergoing a colonoscopy. Stool samples were shipped to a centralized laboratory. Banked residual stool samples were swabbed by laboratory technicians to evaluate the in-lab FIT method. At-home and in-lab FITs were analyzed using the same process and positivity threshold. Both FIT results were compared to each other and to colonoscopy to assess concordance, sensitivity, and specificity. Results: A total of 1,079 stool samples were analyzed using both at-home and in-lab FIT methods. While ~1% of at-home FITs fail due to pre-analytical errors, no in-lab FITs failed analysis. Concordance of results between tests was 93%. Among the 20 subjects with CRC, both at-home and in-lab methods detected 75% (n=15). Among the 231 subjects with AA, the at-home method detected 33% (n=76) and the in-lab method detected 38% (n=88). Positive percent agreement (PPA) for colorectal neoplasia was 87%. Among the 791 subjects with negative findings, specificity for the at-home and in-lab methods were 94% and 95%, respectively. Negative percent agreement (NPA) was 98%. Among the 75 samples with discrepant FIT results, the in-lab FIT more closely aligned with colonoscopy findings relative to the at-home FIT (60% vs. 40%; p < 0.01). Discussion: Our findings suggest that in-lab FIT performance combined with the molecular component of the mt-sRNA test may enhance the diagnostic accuracy of the multi-target test. The in-lab method may also improve test adherence and reduce inadequate sampling.
David Lieberman, MD1, Theodore R. Levin, MD, MS, FACG2, Samir Gupta, MD3, John M. Carethers, MD, FACG3, Aasma Shaukat, MD, MPH, FACG4, Kimberly Kruse, MSc5, Ryan B. Ghannam, PhD5, Erica K. Barnell, MD, PhD6. P2612 - Laboratory-Performed FIT-Enhanced Accuracy and Compliance With mt-sRNA Test for Colorectal Cancer Screening, ACG 2025 Annual Scientific Meeting Abstracts. Phoenix, AZ: American College of Gastroenterology.
