Measurement of ferritin in serum: application in diagnostic use.

A sandwich-type radioimmunoassay for serum ferritin was developed using iron-rich human liver ferritin and evaluated for its clinical usefulness. In young healthy males and females, the mean serum ferritin concentrations were 44 micrograms/L (range 7-158) and 16 micrograms/L (range 4-56), respectively. In anemic patients lower serum ferritin concentrations were found, while in most patients with iron overload serum ferritin concentrations well above 1000 micrograms/L were measured. Comparison of our method with a commercially available radioimmunoassay kit revealed a good correlation, except for sera with very low ferritin concentrations. Comparison with serum iron and transferrin parameters in patients with iron deficiency demonstrated that serum ferritin concentrations might be subnormal in a majority of patients with otherwise normal iron indices. Up to 70% of the ferritin in serum of normal subjects could bind to concanavalin A-Sepharose, indicating its glycoprotein nature. It is concluded that our serum ferritin radioimmunoassay gave reliable results and was useful in the laboratory diagnosis of latent iron-deficiency and in the analysis of the heterogeneity of serum ferritin.