[Evolution of the aluminum concentration in the final dialysis solution: Multicenter study in Spanish dialysis centers].

Aluminium contaminated dialysate is the most dangerous source of aluminium for dialysis patients. The aim of this study was to assess the aluminium content in the dialysis fluid in all the Spanish dialysis centres in 1999 and to compare the results with those obtained in previous studies. For this purpose, all the 275 Spanish centres were invited to participate, we measured the concentration of aluminium in the dialysis fluids in all of them. Aluminium was measured by atomic absorption spectrometry. Since 1988 our laboratory has participated in a external quality assessment scheme for aluminium measurement (University of Surrey) having a good performance (fig. 1). The aluminium concentration in the dialysis fluids were compared with the results obtained in other 2 cross sectional studies performed in 1990 and 1994 following the same methodology. The participating centres were 242 out of 275 (88%). The percentage of centres with a concentration of aluminium in the dialysis fluid lower than 2 micrograms/l has increased throughout the period of study (45% in 1990, 69.8% in 1994 and 81.8% in 1999, fig. 2). One important finding of the new study was the increment in the percentage of centres having undetectable aluminium (< 1 microgram/L) (22.9% in 1990, 41.2% in 1994 and 66.9% in 1999, fig. 3). The safety threshold of 1 microgram/L should be the goal for all the dialysis centres. By contrast, the percentage of centres with aluminium concentration greater than 10 micrograms/L (the old safety threshold to avoid aluminium exposure established by the European Union in 1986) did not show a relevant decrease from 1994 to 1999 (from 5.1% to 4.1% respectively). Taking into account the aluminium content, the quality of the dialysis fluid has improved during the last 10 years, although there is still a non negligible percentage of centres (4.1%) with high aluminium concentration in the dialysis fluid (> 10 micrograms/L).