Liver iron concentration, stainable iron, and total body storage iron.

Liver iron concentration has been determined chemically in 154 liver biopsies and the findings compared with the routine histological assessment of stainable parenchymal iron, performed by an independent observer. There was a significant correlation between liver iron concentration and histochemical grading but the relationship did not have a normal linear form. Absence of stainable iron corresponded to liver iron concentrations below the mean value for control male subjects (77 mug/100 mg dry liver). In general grade 1 siderosis corresponded to liver iron concentrations in the upper part of the control range and grade 2 siderosis to marginally elevated values. The transition from grade 2 to grade 3 (submaximal) siderosis represented a sharp increase in liver iron concentration and as grade 3 siderosis corresponded to a wide range of chemical values it is also the most difficult histochemical grade to interpret in quantitative terms. Grade 4 siderosis invariably indicated heavy iron excess.There was a close correlation between liver iron concentration and measurements of total body storage iron obtained by quantitative phlebotomy in patients with idiopathic haemochromatosis and by determination of DTPA-chelatable body iron in a variety of iron-loading disorders.