Fecal occult blood testing for iron deficiency: A reappraisal

Fecal occult blood (FOB) tests have been evaluated primarily for the applic ation of colorectal cancer screening. Less is known about the performance c haracteristics of FOE tests for the evaluation of iron deficiency, the most common other application, As most clinically important occult gastrointest inal bleeding arises from the proximal gut, it is critical that FOE tests t arget analytes that are stable during the enteric transit. Available data i ndicate that guaiac-type and immunochemical tests are insensitive for the d etection of proximal gut bleeding, and their use may confound the evaluatio n of iron deficiency. In contrast, the heme porphyrin test is sensitive for both proximal and distal sources of occult gastrointestinal bleeding, and this FOE test would appear to be the most rational selection for use in pat ients with iron deficiency or anemia. Outcome data are needed to better ass ess the impact of FOE testing on algorithms for evaluation of iron deficien cy. Copyright (C) 2000 S. Karger AG, Basel.