Reticulocyte hemoglobin equivalent in a thalassemia-prevalent area

Reticulocyte hemoglobin equivalent (Ret-He), a direct measure of the hemoglobin (Hb) in the young red blood cells, has been reported to be useful in the diagnosis of iron deficiency anemia (IDA) but may have some limitations in thalassemia trait. This study evaluated the differences in Ret-He in school-aged children, and assessed the diagnostic value of Ret-He in identifying IDA in a thalassemia-prevalent area.

Blood samples underwent complete blood count analysis, including Ret-He, ferritin, serum iron and total iron binding capacity. Blood samples also underwent Hb typing and a molecular study for α-thalassemia. Receiver operating characteristic analysis was performed to determine the predictive capacity of Ret-He in the diagnosis of IDA. ID was defined as serum ferritin <30 ng/mL and/or transferrin saturation (TSAT) <16%; IDA was defined as serum ferritin <12 ng/mL and/or TSAT <16% with low Hb for age. Normal healthy children (normal controls: NC) had normal iron study, without the thalassemia trait.

Ninety-eight children with a mean age of 12.9 ± 0.6 years were included. Ret-He in the thalassemia trait group (26.7 ± 2.4 pg), ID group (29.0 ± 2.9 pg), IDA group (25.4 ± 2.7 pg), ID + thalassemia trait group (26.6 ± 2.8 pg), and the IDA + thalassemia trait group (24.6 ± 2.3 pg) was significantly lower than in the NC group (30.8 ± 1.7 pg; P < 0.001, 0.01, 0.006, 0.002 and <0.001, respectively). Ret-He had an area under the curve of 0.904 in diagnostic ability for IDA, while a cut-off ≤27 pg had a sensitivity of 91.7% and a specificity of 81%.

Ret-He was lowest in subjects with IDA + thalassemia trait. A Ret-He cut-off ≤27 pg was suggestive of IDA in the present study.