Influence of hemodialysis on selenium blood levels.

Selenium (Se) is considered an essential and very important trace element for humans. Blood Se levels in chronic hemodialysis (HD) patients are frequently reported to be lower than in controls. The aim of this study was to evaluate these lower Se blood levels with respect to the basic renal disease, duration of dialysis treatment, type of the membrane and dialysis solution used. We tried also to use the polynomial curve as a graphical method for rapid evaluation of a large number of Se blood levels. Se blood levels were measured before and after HD in 95 patients on chronic hemodialysis and in a control group of 20 healthy volunteers. Se blood levels were measured by atomic absorption spectrophotometry. Statistically significant increases of Se blood levels were found after HD (p < 0.001). During HD, the relatively high Se blood levels decreased and low levels increased but remained below the range of physiological values. These levels were lower than those of the control group (p < 0.001). Of the different dialysis membranes used, the greatest changes in Se blood levels were measured after HD with cuprophan membranes (p < 0.001). No significant difference in Se blood level in respect to the underlying kidney disease (chronic glomerulonephritis, tubulointerstitial nephritis, polycystic kidney disease, diabetic nephropathy) was revealed. No association of predialytic Se blood levels and the length of dialysis treatment was found. Concluding our results suggests low selenium content in dialysis solution and show that, in respect to the importance of Se for humans, its substitution is desirable.