Immunoradiometric serum ferritin concentration compared with stainable bone-marrow iron as indices to iron stores.

Immunoradiometric analysis has made it possible to measure ferritin reliably in serum. The determination is a sensitive means of assessing body iron because concentrations of ferritin closely parallel the body's reticuloendothelial iron stores. The information provided is similar to that obtained from bone-marrow aspirates or biopsies stained for iron with Prussian Blue. Comparative studies indicate good correlation between iron content in the marrow and serum ferritin, except possibly in patients with leukemia and metastatic tumors to the bone marrow. The clinical value of the assay in relation to other indicators of iron status (i.e., hemoglobin, erythrocyte indices, serum iron and iron-binding capacity, and erythrocyte protoporphyrin) is in its specificity and sensitivity for assaying physiological iron stores.