Carnitine concentrations in dialysed and undialysed patients with chronic renal insufficiency.

Free carnitine, acylcarnitine and total carnitine serum concentrations have been measured in chronic renal insufficiency patients under conservative treatment, in patients under regular haemodialysis treatment and in healthy controls. In the undialysed patients the levels of free carnitine, acylcarnitine and total carnitine were all clearly higher than those of the control group. The free carnitine and total carnitine levels of undialysed subjects were also higher than in regularly haemodialysed patients, showing that dialysis produces plasma carnitine losses that are not compensated for by endogenous synthesis of carnitine (this finding supports published reports of tissue carnitine deficiency in patients undergoing regular haemodialysis). The acylcarnitine levels of dialysed and undialysed patients were not significantly different, however; both were very much higher than that of control group. The hypercarnitinaemia of the patients under conservative treatment suggests that the impairment of renal function causes a reduction in the elimination of carnitine via the kidney.