Introduction:
Iron deficiency anemia (IDA) is still a major global health problem. The prevalence was reported to be highest among children under five years, 39.7%, with the primary contributing cause being dietary iron deficiency (ID). Reticulocyte hemoglobin equivalent (Ret-He) assesses the amount of hemoglobin in reticulocytes. Ret-He is an easy, inexpensive, and applicable diagnostic parameter of iron deficiency. This study aims to determine the role of Ret-He as a diagnostic parameter of ID and IDA in infants 1–4 months old.

Material and methods:
The study was conducted prospectively at 10 Community Health Centers in Banjarbaru, South Kalimantan, from August 2020 to August 2021. In total, 403 infants aged 1, 2, 3, and 4 months met the inclusion and exclusion criteria. Venous blood samples were checked for Ret-He, complete blood count, and peripheral blood smears.

Results:
The incidence of ID and IDA in infants 1–4 months was 10.9% and 58.6%. Ret-He cut-off values for iron deficiency and IDA at 1, 2, 3 and 4 months were 22.25 pg, 20.3 pg, 19.05 pg and 17.55 pg, with sensitivity 7.8%, 2.5%, 7.4%, 8.2%, specificity 94.4%, 95.0%, 96.9%, 98.1%, positive predictive value 85.7%, 66.7%, 83.3%, 80.0%, and negative predictive value 18.1%, 19.6%, 33.0%, 53.6%.

Conclusions:
Ret-He can detect iron deficiency and IDA in a 1–4-month-old baby with high specificity and positive predictive value.