Kamei D, et al. - Patients on maintenance hemodialysis were examined for the association between carnitine profiles before and after dialysis and the erythropoiesis-stimulating agent (ESA) resistance index (ERI), which is a significant prognostic factor. As per stepwise multiple regression analysis, 3-hydroxy isovalerylcarnitine (C5-OH) and stearoylcarnitine (C18) were noted to be independent significant factors of ERI. ERI showed a positive correlation with long-chain C18 acylcarnitine and a negative correlation with short-chain C5-OH acylcarnitine. Responders might be distinguished from nonresponders after L-carnitine administration via determining C5-OH and C18 acylcarnitines at baseline.