Reticulocyte Hemoglobin-Equivalent Potentially Detects, Diagnoses and Discriminates between Stages of Iron Deficiency with High Sensitivity and Specificity

Background: Iron deficiency anemia (IDA) is a global health problem affecting the quality of life of more than 2 billion individuals. The current practice guidelines diagnose and monitor IDA via conventional hematological and iron biomarkers, which take several months before they are corrected under an iron-treatment plan. Reticulocyte hemoglobin equivalent (Ret-He) is used as a marker in most new hematology analyzers to assess iron incorporation into erythrocyte hemoglobin directly. This study aims to examine the efficacy of Ret-He as a marker for iron deficiency (ID) and IDA and investigate whether Ret-He is sensitive to iron therapy. Methods: Two blood samples were drawn from 182 participants for CBC and iron profile measurements. Follow-up samples were drawn from participants with a confirmed diagnosis of ID and/or IDA. Results: Ret-He levels were lower in the ID and IDA groups compared to the control (p < 0.0001), and lower in the IDA group compared to the ID group (p < 0.0001). Ret-He was correlated with ferritin at ID level (<30.0 mg/mL; r = 0.39) and severe IDA (<13.0 ng/mL; p-value < 0.01, r = 0.57). Cut-off values of <28.25 pg for ID and <21.55 pg for IDA showed a higher specificity and sensitivity (ID; AUC: 0.99, sensitivity: 92.73%, specificity: 97.87%) and (IDA; AUC: 0.94, sensitivity: 90.63%, specificity: 92.31%). Finally, Ret-He successfully reflected the iron therapy (p < 0.001) when compared to hemoglobin (Hb) (p = 0.1). Conclusions: Ret-He is a potential marker for detecting and diagnosing different stages of ID with high validity and is very sensitive in reflecting the iron incorporation in a short time.