Unsaturated iron binding capacity and transferrin saturation are equally reliable in detection of HFE hemochromatosis.

Abstract

Unsaturated iron binding capacity (UIBC) has been proposed as an inexpensive alternative to transferrin saturation for detection of hereditary hemochromatosis. The aim of this study was to compare, in a hospital referral clinic, the reliability of transferrin saturation and UIBC for detection of subjects who have inherited HFE (HLA-asociated iron overload) genotypes predisposing to iron overload. Serum transferrin saturation, UIBC, and ferritin were tested in 110 consecutive subjects. Optimum thresholds were determined from receiver operating characteristic curves. Of 110 subjects, 44 carried significant HFE mutations (C282Y/C282Y or C282Y/H63D). In genetically predisposed subjects with biochemical expression, the optimum threshold for transferrin saturation was 43%, giving a sensitivity of 0.88 and specificity 0.95. For UIBC, the optimum threshold was 143 microg/dL (25.6 micromol/L), giving a sensitivity of 0.91 and specificity of 0.95. In patients referred with a family history or clinical suspicion of hemochromatosis, transferrin saturation and UIBC were highly reliable predictors of genotype. In patients referred for investigation of abnormal liver enzymes without a known family history of hemochromatosis, a normal transferrin saturation or normal UIBC was highly reliable in excluding hemochromatosis. Transferrin saturation and UIBC have equal reliability in ability to predict hemochromatosis. UIBC should be considered as an alternative to transferrin saturation in detection of hemochromatosis.