Measuring interval cancers in population-based screening using different assays of fecal occult blood testing: the District of Florence experience.

The fecal occult blood test (FOBT) has demonstrated its efficacy in reducing mortality from colorectal cancer (CRC). The guaiac-based FOBT has been criticized for its low sensitivity. In this study, two different assays for FOBT (guaiac or an immunochemical test based on reversed passive hemagglutination [RPHA]) were tested for comparison within a population-based screening program for colorectal cancer in the province of Florence (Italy).