Ferritin as an index of bone marrow iron stores.

We examined the relationship of serum ferritin to bone marrow iron stores in 73 anemic male medical inpatients with liver disease, alcoholism, chronic inflammatory disease, and malignancies. A correlation of r = 0.75 (P less than .00005) was found between serum ferritin and bone marrow iron stores (BMIS) for the entire group. Liver disease as manifested clinically or by increased levels of serum glutamic-oxaloacetic transaminase did not appear to significantly affect this relationship. Patients with folic acid deficiency did tend to have a disproportionate increase in ferritin in relation to BMIS, but this did not seem to destroy the usefulness of ferritin levels. A useful clinical rule seems to be that serum ferritin of greater than 100 ng/ml tends to exclude iron deficiency, and a level of less than 30 ng/ml tends to confirm decreased iron stores.