Tests for evaluating iron metabolism are generally used as initial or screening tests for HH as they will detect the phenotypic expression of HH. These tests include serum iron (SI), transferrin (Tf), or total iron-binding capacity (TIBC), transferrin saturation, serum ferritin (SF), and unsaturated iron-binding capacity (UIBC). The serum ferritin assay is also used to assess the effectiveness of HH treatment.
Molecular (DNA) analyses for HFE mutations are considered to be confirmatory tests for HH, which may be ordered reflexively in patients with elevated iron results.
Laboratories should establish their reference intervals for iron metabolism assays. In general, reference intervals vary by sex and by the method used for the assays discussed in the following section. Typical reference intervals are included in the following sections and in the testing algorithm for instructive purposes only and should not be used for evaluating actual patient data.
The results of laboratory tests assessing iron metabolism should be interpreted cautiously because several preanalytical and physiologic factors can affect the results. Repeating elevated test results on fasting specimens is often advisable.
