Sinlapamongkolkul P.Pusongchai T.Buaboonnum J.Satayasai W.Surapolchai P.Mahidol University2026-04-142026-04-142026-01-01Siriraj Medical Journal Vol.78 No.1 (2026) , 68-78https://repository.li.mahidol.ac.th/handle/123456789/116208Objective: Reticulocyte hemoglobin equivalent (RET-He) has been identified as a useful marker for diagnosing and monitoring iron deficiency anemia (IDA). This study evaluated anemia prevalence and assessed RET-He’s effectiveness in detecting IDA in pediatric inpatients with high thalassemia burden. Materials and Methods: A cross-sectional design was employed involving children aged 6 months to 15 years admitted with anemia. RET-He and red blood cell (RBC) indices were compared to explore diagnostic implications. Results: Among the 881 pediatric inpatients included during the study period, 17% (154 patients) were identified as having anemia. IDA was the major cause of anemia (98%), including IDA (70.1%) and IDA coexisting with thalassemia (27.9%). Median RET-He (IQR) of all anemic patients was 21.05 (18.70, 24) pg. Notably, RET-He values were lower in patients with combined IDA and thalassemia than in those with IDA alone (p = 0.004). Significant correlations were observed between RET-He and RBC indices such as mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH). With a cut-off of ≤20.3 pg, RET-He showed moderate sensitivity (70.3%) and specificity (60.5%) for diagnosing IDA. Conclusion: These findings advocate for RET-He’s use as an iron status marker in hospitalized children, especially in areas endemic for thalassemia. Low RET-He in non-responders to iron therapy should raise suspicion of underlying thalassemia.MedicineArticleSCOPUS10.33192/smj.v78i1.2774562-s2.0-10503501556722288082