BACKGROUND: Darbepoetin alfa (DA) is an erythropoietin-stimulating agent (ESA) preferably administered through intravenous (IV) route in hemodialysis (HD) patients. Although some in vitro studies suggest the possibility of partial adsorption of ESAs in dialysis membranes (Mb) and lines, these data are not clinically confi rmed.METHODS: This 12-month, prospective, single-center cross-over study assessed the impact of the time of IV DA injection during HD on hemoglobin (Hgb) level and ESA dosing. A total of 90 HD patients received IV DA once every other week (Q2W), delivered at 2 possible time points: the middle or end of the HD session. After 6 months, the injection time point was crossed over to the other timing modality for another 6 months.RESULTS: Demographics for both groups of patients were similar. Mean Hgb level remained stable from baseline to month 6 (not signifi cant) for both timing modality groups. The same was observed for DA dose. Hemodialysis session parameters, nutritional status, and Kt/V were similar and stable during the study. Mean transferrin saturation was 44% and serum ferritin was Ն100 g/L in more than 92% of patients. Iron supplementation remained unchanged and there were no blood transfusions during the study.CONCLUSIONS: Q2W DA maintained target Hgb concentrations. The lack of difference in Hgb levels and DA dosing between the 2 injection timings suggests a lack of clinically signifi cant adsorption/interaction between DA and dialysis Mb/lines. Therefore, timing of IV DA administration can be fl exible and adapted to the routine practice of each local dialysis unit.