Background: Iron deficiency is the main cause of failure to respond to erythropoietin (EPO) in haemodialysis patients. Several laboratory tests to detect the deficiency, ferritin and transferrin saturation (TSat) are the most commonly used but its limitations in this patient population are necessary to find other parameters to improve the identification of iron-deficient state.
Objective: To evaluate the ability of Reticulocyte Hemoglobin Equivalent (RET-He) to predict iron deficiency, taking as a reference standard to the increase of hemoglobin in response to iron intake.
Materials and methods: 44 patients on chronic hemodialysis and fixed-dose EPO received 400 mg of intravenous iron. Were measured Hb, Ret-He, IRF, and ferritin prior to iron administration. After 20 to 30 days of completion of loading the patients were classified as responders if hemoglobin increased by at least 0.8 g / L and non-responders if this increase did not occur.
Result: 25 patients were responders, the ROC curves analysis showed the Ret-He with the largest AUC of 0.862 similar to the AUC of 0.833 that showed the IST, but the first is more sensitive (72% CI 95%: 51-88% vs 52% 95% CI 31-72%) and similar specificity (94.7% CI 95%: 74-100% vs 100% 95% CI 82-100%). Ferritin AUC was 0.772 and finally the IRF AUC was 0.7. The Ret-He, to a cutoff of 29.5 pg was the best combination of sensitivity and specificity (72 and 94.7 respectively), and the sensitivity of the combination Ret-He/IST rose to 80% specificity 94.7%.
Conclusions: According to these results it could consider to Ret-He and the Ret-He/IST combination of clinical utility for the identification of the iron deficit in patients in chronic haemodialysis.