Free erythrocyte protoporphyrin assay in the diagnosis of iron deficiency in the anemic aged subject. A prospective study of 103 anemic patients.

We determined the relative value of the free erythrocyte protoporphyrin (FEP) assay compared to those of total iron-binding capacity (TIBC) and serum ferritin in the diagnosis of iron deficiency in a population of elderly anemic subjects. One hundred and three patients, 65 to 98 years old (mean +/- SD: 81.5 +/- 8.8), with hemoglobin levels of less than 110 milligrams (mean +/- SD: 97 +/- 12, range 53-109) were included in the study. In the patients with iron-deficiency anemia due solely to chronic bleeding, mean values for the three parameters were highly different from those in patients without chronic bleeding. In the patients with anemia due to an association of chronic bleeding and chronic inflammation, the mean FEP value was very significantly different (p less than 0.001) from that in the patients with chronic inflammation but without bleeding, whereas this was not the case for TIBC or serum ferritin. The sensitivity of FEP in the diagnosis of iron deficiency due to chronic bleeding in this population of anemic subjects was 60% (specificity 90%), compared to 13% (specificity 96%) for TIBC and 20% (specificity 100%) for serum ferritin. The FEP assay thus emerges as being highly suitable for the diagnosis of iron-deficiency anemia in the elderly subject, particularly when bone marrow is not examined.