Erythrocyte protoporphyrin in the detection of iron deficiency.

Any decrease in the availability of iron for incorporation into the heme moieties of hemoglobin results in an increase in the erythrocyte protoporphyrin concentration. Our aim was to compare protoporphyrin concentrations, determined spectrophotometrically, with body iron stores, as assessed from the amount of iron demonstrable by Prussian blue staining of bone marrow aspirates. The mean protoporphyrin concentration (175 mu-g/dl) in the erythrocytes of a group of patients with markedly decreased stainable marrow iron or no iron was significantly greater (P less than .001) than the mean concentration (76 mu-g/dl) in a comparable group with adequate bone marrow iron stores, except in the presence of certain interfering conditions. These results suggest that the erythrocyte protoporphyrin test may be a useful addition to the methods now available for assessing disorders of heme synthesis, the most common of which is iron deficiency.