Use of iron deficiency flag of the hematology analyzer Sysmex XN-3000 for early iron-deficient erythropoiesis diagnosis

Abstract

Background: Classical biomarkers (e.g., ferritin, transferrin, etc.) for diagnosis of iron deficiency (ID) are affected by inflammatory processes and influenced by circadian variations and dietary intake. In iron-deficient erythropoiesis, the lack of total body iron limits the production of hemoglobin and other iron-requiring compounds, resulting in iron-deficient erythropoiesis. The aim of the study was to evaluate the diagnostic performance of the Iron-Deficiency (Iron-Def) flag and its possible role as diagnostic algorithm for the identification of patients with iron-deficient erythropoiesis. Methods: Data of 3,489 consecutive patients (mean age: 46.6 years, standard deviation: ±25.9 years), referred for routine diagnostics to the Laboratory of Clinical Pathology of Hospital ASST Nord Milano, Sesto San Giovanni (Milano, Italy), were retrospectively analyzed. A complete hematological testing was performed to identify iron-deficient erythropoiesis. The correlation among the Iron-Def flag and other haematological parameters was performed by the Spearman’s rank order test. Receiver operating characteristic (ROC) curves have been analysed to evaluate the diagnostic performance of the Iron-Def flag for detecting iron-deficient erythropoiesis. Results: A significant negative correlation was observed between Iron-Def and haematocrit (HCT), haemoglobin (HGB), mean cell volume (MCV), mean cell haemoglobin (MCH), percentage of macrocytic red cells (MacroR%), reticulocyte haemoglobin equivalent (RET-He), whereas a positive correlation could be found with red blood cells (RBC), red blood cell distribution width (RDW)-coefficient of variation (CV), percentage of microcytic red cells (MicroR%). The ROC curve analysis shows that the most accurate Iron-Def cut-off value was >80. This cut-off showed a good diagnostic performance with the area under the curve (AUC) of 0.855 [95% confidence interval (CI): 0.837–0.873]. Conclusions: Our work suggest that Iron-Def flag may be an inexpensive, easy and fast index for initial screening of iron-deficient erythropoiesis.