Fecal occult blood testing for colorectal cancer screening: Use the finger

OBJECTIVE: Fecal occult blood testing (FOBT) has been widely underused as a means of colorectal cancer screening. Less than 35% of Americans have had the recommended FOBT in the last 5 yr. Guidelines suggest FOBT of three spo ntaneously passed stools (SPS) on a prescribed diet. Testing stool obtained by digital rectal exam (DRE) is discouraged because its yield in colorecta l cancer screening is unknown. The aim of this study is to compare the posi tive predictive value of FOBT for the detection of colorectal neoplasia don e by SPS versus DRE in asymptomatic outpatients. METHODS: Medical records and endoscopic reports of all patients who underwe nt colonoscopy between 1984-1999 for a positive FOBT were reviewed. Only as ymptomatic outpatients whose indication was colorectal cancer screening wer e included. The method of FOBT was confirmed as either SPS or DRE. chi (2) was used to compare the yield of detecting colorectal neoplasia between SPS and DRE. RESULTS: A total of 165 patients with a mean age of 61 yr (range 33-85) wer e included (84 patients were women). Neoplasia was detected in 29 of 80 (36 %) with SPS and 28 of 85 (33%) with DRE (p = 0.18). CONCLUSIONS: The positive predictive value of FOBT on DR-E for detecting ne oplasia is similar to that of SPS in asymptomatic outpatients undergoing co lorectal cancer screening. Positive FOBT on DRE warrants colonoscopic evalu ation. Hemoccult testing by DRE may be performed in the office to increase patient compliance with colorectal cancer screening. A negative FOBT on DRE should be followed up with FOBT of SPS. (C) 2001 by Am. Coll. of Gastroent erology.