Sideropenic anemia in rheumatoid arthritis: diagnostic usefulness of serum ferritin, unsaturated transferrin and induced urinary siderosis.

The various erythrocyte indices, serum iron, unsaturated iron binding capacity, serum ferritin and sideruria after desferrioxamine were measured in a group of 30 patients with active Rheumatoid Arthritis and anemia. The patients were subdivided into two groups of 23 and 7 subjects based on the presence or absence of marrow iron stores, respectively. Significant differences in the mean values of unsaturated iron binding capacity (P less than 0.001), serum ferritin (P less than 0.01) and sideruria after desferrioxamine (P less than 0.001) were observed between the two groups of patients by statistical analysis. Unlike the other indices, the values assessed in the first and the second group of patients as for the above parameters did not overlap. A negative correlation index and a positive one of high significance (P less than 0.001) was found between the values of serum ferritin and those of unsaturated iron binding capacity and sideruria after desferrioxamine, respectively. The above results demonstrate that even in active Rheumatoid Arthritis a concomitant iron deficiency can be diagnosed by means of non-invasive, quantitative and easily reproducible methods.