The value of serum iron studies as a test for iron-deficiency anemia in a county hospital.

To evaluate the performance of serum iron studies as a diagnostic test for iron-deficiency anemia in a county hospital, the authors identified retrospectively all general medicine patients who had had bone-marrow aspirates for the work-up of non-macrocytic anemias from 1978 through 1983. Re-reading a sample of aspirates from the 254 study patients (42 with iron deficiency) verified the presence or absence of iron. Analysis with logistic regression, likelihood ratios, and receiver operating characteristic curves demonstrated that the total iron-binding capacity (TIBC) performed markedly better as a diagnostic test than did the transferrin saturation test. While no single TIBC level was diagnostic, the TIBC provided a good estimate of the probability of iron-deficiency anemia.