Guaiac-Based Fecal Occult Blood Screening Performs Poorly

Guaiac-based fecal occult blood test (gFOBT) screening for colorectal cancer (CRC) has been proven in randomized trials to reduce CRC mortality. However, when compared with fecal immunochemical testing in randomized trials and in cohort studies in which colonoscopy screening patients have been pretested with fecal blood screening, gFOBT is consistently outperformed by immunochemical testing.

To further evaluate the diagnostic performance of gFOBT screening, investigators in Germany analyzed 20,884 colonoscopies performed for a positive gFOBT and 182,956 primary-screening colonoscopies.

In the gFOBT group compared with the primary-screening group, positive likelihood ratios for detecting nonadvanced adenoma, advanced adenoma, and cancer were 1…