Reticulocyte Hemoglobin Equivalent (Ret-He) as a Marker of Iron Deficiency Anemia in Acutely Ill Hospitalized Children.

OBJECTIVES

To evaluate diagnostic utility of reticulocyte hemoglobin equivalent (Ret-He) in identifying iron deficiency anemia (IDA) in acutely ill hospitalized children in comparison to serum ferritin.

METHODS

After excluding chronic inflammatory and anemic conditions unrelated to iron deficiency (ID), patients were categorized as (1) IDA: low hemoglobin+ microcytosis+ red-cell-distribution-width (RDW) index >220, (2) Non-anemia-iron-deficiency (NAID): normal haemoglobin+ microcytosis+ RDW index >220 and (3) Normal-group: normal hemoglobin+ normocytosis. Diagnostic utility indices for IDA were calculated using low hemoglobin+ microcytosis + RDW index >220 as surrogate standard. Correlation coefficients and receiver-operating-characteristic (ROC) curve cut-offs for Ret-He and ferritin were calculated.

RESULTS

Anemic (n = 180) and non-anemic (n = 66) acutely ill children, after exclusion criteria, were classified into IDA (n = 102), NAID (n = 14) and normal (n = 21). IDA group had significantly lower Ret-He levels (p <0.001). Ferritin levels showed no significant difference (p = 0.062). For IDA detection, Ret-He cut-off of 27.7 pg yielded sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of 87.2%, 80.9%, 95.7%, 56.7% and 86.2% whereas ferritin at cut-off of 147.0 ng/ml showed values of 58.8%, 66.7%, 89.5%, 25.0% and 60.2% respectively. For NAID detection, Ret-He cut-off of 29.1 pg showed sensitivity, specificity, PPV, NPV and accuracy of 71.4%, 57.1%, 52.6%, 75.0% and 62.9%, while ferritin at cut-off of 153 ng/ml showed values of 57.1%, 61.9%, 50.0%, 68.4%, and 60.0% respectively.

CONCLUSIONS

Ret-He demonstrated superior diagnostic utility compared to serum ferritin for IDA in acutely ill hospitalized children. Optimal cut-off for serum ferritin for IDA was significantly higher than WHO reference standard.