Approximately 10% of Returned Fecal Immunochemical Tests Unsatisfactory

One in 10 patients returned an unsatisfactory fecal immunochemical test (FIT), according to results of a study published in Cancer Epidemiology, Biomarkers & Prevention.

Stool-based colorectal cancer screening modalities are cost-effective, noninvasive, convenient, and can be effective when completed correctly. Recommendations suggest that less than 5% of tests may not be processable; however, few large-scale studies have been performed to assess FIT failures.

This population-based, retrospective cohort study was conducted using data from Parkland Health. Patients (N=56,980) who completed 1 or more FITs between 2010 and 2019 were evaluated for test completion.

The patients comprised 61.3% women, 39.7% were aged 50 to 54 years, 48.7% were Hispanic, and 55.3% had a comorbidity score of 0.

Overall, 5819 FITs were unsatisfactory, primarily due to insufficient or unsatisfactory sample (51%), incomplete labeling (27%), age of specimen (13%), and broken or leaking container (8%).

Significant predictors for unsatisfactory FIT included prior unsatisfactory FIT (odds ratio [OR], 2.74), exposure to mailed FIT outreach (OR, 2.66), Medicaid compared with commercial insurance (OR, 1.42), and Polymedco FIT test tube compared with hemoccult 3-card test (OR, 1.32), among others.

Among unsatisfactory FITs, 65% had follow-up within 15 months but fewer than half of them (40.7%) had a subsequent FIT.

Patients with unsatisfactory FIT who were more likely to undergo a subsequent colorectal cancer screening test within 15 months were exposed to mailed FIT outreach (OR, 1.92), had Polymedco FIT test tube compared with hemoccult 3-card test (OR, 1.77), and had more primary care encounters (OR, 1.05).

The study authors concluded, “[O]ne in ten of the nearly 57,000 FIT completed for colorectal cancer screening could not be processed by a laboratory, mostly due to errors in completing the test. That most unsatisfactory stool tests did not have a subsequent screening test highlights the need for systems to have a better, more comprehensive approach to flagging and following up unsatisfactory FIT.”

Reference

Liu PH, Nair RG, Skinner CS, et al. Unsatisfactory fecal immunochemical tests for colorectal cancer screening: prevalence, reasons, and subsequent testing. Cancer Epidemiol Biomarkers Prev. Published online November 15, 2023. doi:10.1158/1055-9965.EPI-23-0507