Detection of iron restriction in anaemic and non-anaemic patients: New diagnostic approaches.

OBJECTIVE: The aim of this study was to detect iron restriction in non-anaemic patients and iron-restricted erythropoiesis (IRE) in patients with anaemia.

METHOD: Haematologic indices and biochemical markers of iron deficiency (ID) were determined using the clinically accepted cut-off level for serum ferritin of ≤30 μg/L as reference of ID. To evaluate the prevalence of iron restriction and IRE in patients with higher ferritin levels, we used the thresholds of the markers of ID as reference.

RESULTS: In the anaemic group, 17.1% of patients with ferritin levels >30 μg/L had IRE. The number of patients with IRE declined with increasing ferritin concentration. Approximately 14% of patients without anaemia and ferritin levels >30 μg/L had iron restriction because of iron-sequestration syndromes. About 30% of the anaemic patients with IRE had ferritin concentrations in the range >300 μg/L, but no patient of the non-anaemic group.

CONCLUSIONS: Detection of iron restriction and IRE in patients with ferritin levels >30 μg/L is not possible with a single test used in isolation. Based on the results, we have developed a scoring system to provide optimal guidance for the evaluation of iron restriction in non-anaemic patients and iron-restricted erythropoiesis (IRE) in patients with anaemia.