Serum ferritin, free erythrocyte protoporphyrin, and urinary iron excretion in patients with iron disorders.

Tests to evaluate body iron stores were compared in patients with iron deficiency and the anemia of chronic disease. The serum ferritin assay separated these disorders in 20 of 22 patients. One discrepancy was explained by the concomitant association of both disorders. From this study and review of literature a low serum ferritin level is a good indication for iron therapy. The serum ferritin assay is a clinically useful test in lieu of bone marrow estimation of body iron stores to detect patients with iron deficiency. Total iron binding capacity levels when high-normal or elevated are sometimes helpful as a screening test in separating iron deficiency from the anemia of chronic disorders. Free erythrocyte protoporphyrin values were elevated in both conditions but were higher in iron deficiency than in the anemia of chronic disorders with considerable overlap of values. Urinary iron excretion with deferoxamine was not helpful in separating these disorders but is a useful test to establish iron overload. An elevated serum ferritin level is usually found with disease of iron overload but serum iron levels, deferoxamine iron excretion tests, and liver biopsy for estimation of iron stores are still beneficial diagnostic aids.