A rapid high performance liquid chromatographic method for the analysis of choline in human plasma and peritoneal dialysis effluent: Application in the assessment of choline loss in continuous ambulatory peritoneal dialysis

Mesothelial cells lining the peritoneal cavity utilize choline in the synthesis of a phosphotidylcholine-rich material thought to play a role in peritoneal homeostasis. This function is particularly important for patients undergoing continuous ambulatory peritoneal dialysis (CAPD). To assess choline loss in these patients, we measured choline in plasma and peritoneal dialysis effluent (PDE) by a rapid high performance liquid chromatography (HPLC) procedure that combined electrochemical detection with an immobilized enzyme reactor. Chromatography was performed directly on plasma and PDE ultrafiltrates. In 30 patients, the amount of choline lost to the dialysate was 129 ± 49 μmol per day and 32 ± 8 μmol per dwell (mean ± SD). The average plasma choline concentration was 22.5 μmol/L, a value somewhat higher than the mean value reported for noraml adults (9 μmol/L). The average PDE choline concentration was 14 μmol/L. There was a positive correlation between daily choline loss of dialysate and plasma choline concentrations ( r = 0.826).