A study published in The Lancet Gastroenterology & Hepatology found that two-sample fecal immunochemical tests did not significantly improve detection rates over one-sample FIT.
Researchers put subjects through four rounds of either 1-FIT or 2-FIT screening between 2006 and 2015. About 7,310 1-FIT participants completed at least one round of screening, and 2,269 2-FIT participants completed at least one round of screening.
What they found:
1. The 1-FIT cohort had a 19.2 percent cumulative positive rate, lower than the 28.5 percent rate the 2-FIT cohort posted.
2. Cumulative positive predictive value was higher in the 1-FIT cohort (33 percent) than the 2-FIT cohort (24.2 percent).
3. Diagnostic yield of advanced neoplasia was higher in the 2-FIT cohort (4.7 percent) than the 1-FIT cohort (4.4 percent).
4. Eight people in the 1-FIT cohort and two people in the 2-FIT cohort had interval colorectal cancers.
Researchers said one-sample FIT programs were preferred to two-sample FIT programs because, "Four rounds of 2-FIT screening with a low faecal haemoglobin cutoff level did not result in a significant increase in diagnostic yield or a decrease in interval colorectal cancers compared with 1-FIT, despite higher colonoscopy demand."