An occult blood test finds blood in the stool by placing a small sample of feces on chemically treated cards. The presence of blood in the feces may be the only indicator of CRC.

Two of the most commonly used test cards were compared for efficacy in a random sample of 15,011 Dutch residents who were invited to participate. The residents were sent, with instructions on usage, either three Hemoccult II guaiac-based fecal occult blood test cards, (gFOBT) (Beckman Coulter, Fullerton, CA, USA) or one OC-Sensor micro-immunochemical FOBT (FIT) kit (Eiken Chemical, Tokyo, Japan). A gFOBT was considered positive if one or more panels were positive and the FIT was positive at a cut-off value of 100 ng hemoglobin/mL according to the manufacturer's instructions. An additional third of the population were invited for flexible sigmoidoscopy (FS) for CRC screening.

The study was carried out at the Erasmus University Medical Center (Rotterdam, The Netherelands). Approximately 50% of the residents returned their gFOBT samples, which required three bowel movements, while 61.5% sent the single FIT card back to laboratory. The FIT was positive in 4.8% of cases and in 2.8% of the gFOBT responders. Colonoscopy was indicated for those screened with a positive gFOBT or FIT. The detection rate of advanced neoplasia was significantly higher in the FIT positive cohort (2.4%) than the gFOBT group (1.1%).

This randomized population-based CRC-screening trial demonstrated superior participation and detection rates for FIT compared to gFOBT screening. FIT screening should therefore be strongly preferred over gFOBT screening. FS screening demonstrated a higher diagnostic yield per 100 invitees than both FOBTs. The results of the study were published in August 2009 in the journal Gut.

Related Links:
Beckman Coulter
Eiken Chemical
Erasmus University Medical Center