Acidic isoferritin（AIF） was isolated and purified from human heart muscle.Antisera against AIF were generated by immunizing rabbits and purified in affinity chromatography column which was conjugated with AIF. The immunogloublins against AIF were made in solid-phase. 125I-monoclonal antibodies against H subunit of AIF（AIF-H） was prepared by the chloramine-T method. The AIF-H solid-phase IRMA was established and the data were processed by the automatic spline function.The intra- and interbatch coefficients of variation were 2.443% and 10.160%respectively. The sensitivity was 0.736 μg/L and the recovery was 92.293%. The measuring range was 1.472-320 μ g/L and ED5o was 23.05 μ g/L. No cross-reaction was observed with AFP

CEA and LF

but there was 3.125% with ferritin. A parallel experiment demonstrated that seruxn matrix had no interference with this method.The level of serum AIF-H in 40 healthy men and women was 3.75 ± 1.85 μ g/L and 2.92± 0.96 μ g/L respectively while it was 8.39± 3.87 μ g/L in 10 patients with hepatoma. This method may therefore provide a valuable tool for diagnosis of tumor

especially for basic and clinical study of hepatoma.