Red cell ferritin and iron stores in patients with chronic disease

Serum and red cell ferritin were determined in a heterogeneous group of 59 patients with chronic disease undergoing a bone marrow biopsy. There was very little correlation between serum and red cell ferritin (r = 0.53). Although serum ferritin increased in relation to increased bone marrow iron stores, only 1 out of 8 patients with absent marrow iron stores and none of 8 patients with reduced marrow iron stores had a decreased serum ferritin. In contrast, 6 of 8 patients with absent iron stores had a reduced red cell ferritin concentration. There was no significant difference between the mean red cell ferritin of the patients with reduced, normal and mild-moderately increased marrow iron stores (30, 26 and 34 ag/cell). Red cell ferritin was decreased in 78% of a group of 32 patients with a low mean cell volume. In the patients studied, red cell ferritin was a better indicator of absent iron stores than serum ferritin. However, red cell ferritin did not detect a reduction in the iron status until the marrow iron stores were completely depleted. Apparently, during normal erythropoiesis the primitive erythroblasts continue to take up iron irrespective of the amount of iron available in the stores.