Trace elements in blood and dialysate among continuous ambulatory peritoneal dialysis patients: A prospective, multicenter collaborative study

Trace elements (TEs) such as copper (Cu) and zinc (Zn) may play an important role in normal physiology, while others such as aluminum (Al) and lead (Pb) may cause organ dysfunction. It is well known that there are differences in TE concentrations between renal failure patients and normal populations. The purpose of this study was to determine blood levels of various TEs in uremic patients on continuous ambulatory peritoneal dialysis (CAPD). Plasma levels of Al, Zn, and Cu, and blood levels of cadmium (Cd), Pb, and mercury (Hg), were measured in 51 CAPD patients and 153 apparently healthy control subjects. All of the CAPD patients had higher levels of Al, Cu, Cd, and Hg and lower levels of Zn; however, the levels of TEs, with the exception of Al, were within the accepted limits. Age only increased the levels of Cu and Hg, and the duration of CAPD was not correlated with the blood levels of any of the TEs tested. The fresh dialysis solution contained scant amounts of Al, Cu, Cd, Pb, and Hg, but higher levels of Zn were noted. Although TE levels among CAPD patients are either increased or decreased by the procedure, the concentrations remain within normal limits, with the exception of Al. The data from this study provide an insight for further studies of TE imbalance among CAPD patients. The consequence of a higher Zn concentration in the fresh dialysis solution deserves further observation.