Fecal occult blood testing in hospitalized patients

We have evaluated the diagnostic value of the fecal occult blood test (FOBT) in hospitalized patients. We reviewed the medical records of patients who had a positive FOBT not associated with a large gastrointestinal bleed, and who had a subsequent complete evaluation of their gastrointestinal (GI) tract. Of the 50 subjects who met the study criteria, 21 had various GI symptoms and 13 reported weight loss. Patients taking medications that may influence the FOBT result were distributed as follows: 15 were taking nonsteroidal antiinflammatory drugs, eight were taking iron supplementation, three were using steroid drugs, and three were taking anticoagulant drugs. Nonneoplastic lesions were found in 47 patients. Neoplastic lesions were discovered in 11 patients: seven had adenomatous polyps, two had colorectal cancer, one had gastric cancer, and one had duodenal cancer. Only two of seven patients with adenomatous polyps had lesions > 1 cm. In the study population, the positive predictive value of FOBT for finding colonic neoplasms was 18% and for any GI neoplasm it was 22%. Our data indicate that in hospitalized patients (a) the yield of colonic neoplasms from FOBT is approximately 50% less than that in healthy outpatients, and (b) a positive FOBT test is unlikely to lead to the detection of GI malignancy in the absence of suggestive clinical findings.