Murphy CC, et al. - Previous researchers have shown that the risk of developing colorectal cancer mortality decreases upon screening with fecal occult blood tests (FOBT) and failure to complete repeat tests may compromise screening effectiveness. Thus, researchers of the current systematic review investigated repeat FOBT across diverse healthcare settings. Via searching MEDLINE, Embase, and the Cochrane Library, they identified studies reporting repeat FOBT two or more screening rounds. These studies estimated repeat FOBT as (i) proportion of Round 1 participants completing repeat FOBT in Round 2; (ii) proportion completing two, consecutive FOBT; or (iii) proportion completing three or more rounds. FOBT completion in two rounds ranged from 16.4% to 80.0%; in studies examining three or more rounds, FOBT completion ranged from 0.8% to 64.1%. Mailed outreach (69.1% to 89.6%) vs opportunistic screening (24.6% to 48.6%) was correlated with higher repeat FOBT. As prevalence generally declined in successive screening rounds, the researchers emphasized implementing interventions that increase and maintain participation in FOBT to optimize the effectiveness of this screening strategy.