Reticulocyte Hemoglobin Equivalent: Diagnostic Performance in Assessment of Iron Deficiency in Patients with Hypothyroidism

Abstract

Introduction. Iron deficiency affects approximately 30% of the world population and is frequently encountered in hypothyroid patients. Early recognition and prompt treatment of iron deficiency in hypothyroid patients lead to a favorable outcome. The aim of this study is to prove the usefulness of reticulocyte hemoglobin equivalent (Ret-He) as a reliable and effective tool in diagnosis of iron deficiency in hypothyroid patients. Materials and Methods. 154 patients with hypothyroidism were included in the study. They were divided into 4 groups. Group 1 included 66 hypothyroid patients without iron deficiency. They were taken as controls. Group 2 included 66 hypothyroid patients with iron deficiency anemia (IDA). Group 3 included 12 hypothyroid patients with iron deficiency but without anemia (ID). Group 4 included 10 hypothyroid patients which had concomitant iron deficiency with anemia of chronic disorder (ACDC). Ret-He was measured by analyzing blood samples on System XN 350. Thyroid profile, serum ferritin, and biochemical data were measured by an automated analyzer. Statistical analysis was performed by using SPSS 23. Results. Ret-He was significantly lower with ( $p<0.001$ ) in group 2 (hypothyroid patients with IDA), group 3 (hypothyroid patients with ID), and in group 4 (hypothyroid patients with ACDC) as compared to controls in group 1 (hypothyroid patients without iron deficiency). After ROC analysis area under the curve (AUC) of Ret-He for hypothyroid patients with IDA was 0.96 at cutoff 28.5 pg with sensitivity of 93% and specificity of 90%. AUC of Ret-He in the hypothyroid group with ACDC was 0.99 at cutoff 30.8 pg with sensitivity of 90% and specificity of 90%. AUC of Ret-He in hypothyroid patients with ID was 0.97 at cutoff 31.7 pg with sensitivity of 91% and specificity of 70%. Conclusion. Ret-He is a reliable, rapid, and cost-effective tool for diagnosing iron deficiency in hypothyroid patients.