Comparison of Immunochemical and Guaiac-Based Occult Fecal Tests with Colonoscopy Findings in Symptomatic Patients

Purpose: The fecal occult blood test is recommended for detecting colorectal cancer in asymptomatic patients. These tests are based on the fact that colonic cancer and large polyps spontaneously tend to bleed. Whether these tests are of any use in symptomatic patients remains debated. Our aim was to compare guaiac-based test and immunochemical test in symptomatic patients requiring total colonoscopy, to correlate these results to colonoscopy findings and to establish the performance of these tests for mucosal colonic lesion detection other than colorectal cancer. Methods: Prospective study aimed at including 100 consecutive symptomatic patients whose condition required a total colonoscopy. All patients had 12 hours before endoscopy both tests performed on the same stool sample. Results: 113 patients were included of which 100 had complete colonoscopy. Guaiac-based occult fecal test and the im- munochemical test had similar performances whatever the mucosal injury and whatever the location of the injury were found at colonoscopy. Conclusions: Despite numerous previous studies reporting higher performances of the immunochemical test over the guaiac-based test, the incremental increase performance of the immunochemical test remains non significant in the setting of the current study. Therefore generalization of this test should be taken with caution.