Are fecal immunochemical test characteristics influenced by sample return time? A population-based XXXX screening trial.

@entity1241 @entity14
OBJECTIVES: @entity1241 ( @entity1241 ) are preferred over guaiac-based fecal occult blood testing as @entity14 ( @entity14 ) screening tool. However, hemoglobin (Hb) degradation over time may influence @entity1241 outcome. We therefore evaluated the effect of sample return time on @entity1241 performance characteristics in a population-based @entity14 screening trial. METHODS: A representative random sample of the Dutch population (n=17,677), aged 50-74 years, was invited for @entity1241 screening (OC-Sensor Micro; cutoff >=  50 ng Hb/ml). Sample return time was defined as the interval in days between fecal sampling and @entity1241 laboratory delivery. Moreover, a random sample of positive FITs were selected to be stored at room temperature and re-tested every 3-4 days. RESULTS: In total, 8,958 screenees fulfilled our inclusion criteria. The mean sample return time was 3 days (     3). Overall, 792 screenees (8.8%) had a positive test. Between the sample return time groups, the positivity rate (PR) varied between 7.7 and 9.0%. No statistically significant associations were found between PR or detection rate (DR) and the different sample return time groups (P value=0.84 and 0.76, respectively). For the laboratory experiment, 71 positive FITs were stored at room temperature and re-tested with standard intervals. The mean daily fecal Hb decrease was 5.88% per day (95% confidence interval 4.78-6.96%). None of the positive FITs became negative before 10 days after fecal sampling. CONCLUSIONS: This population-based @entity14 screening trial demonstrates that both the PR and DR of FITs do not decrease with prolonged sample return times up to 10 days. This means that a delay in sending the @entity1241 back to the laboratory, of up to at least 1 week, does not necessitate repeat sampling in case of a negative test result. These data support the use of @entity1241 -based screening as a reliable tool for nationwide @entity14 screening programs.
