Concentration of uric acid removed during dialysis. estimated by multi wavelength and processed ultra violet absorbance spectra

The aim of this study was to estimate the concentration of uric acid (UA) optically by using original and processed ultra violet (UV) absorbance spectra's of the spent dialysate. Also the effect of using several wavelengths for estimation was examined. Ten uremic patients from Tallinn and ten from Linkoping, during 30+40 hemodialysis treatments, were followed at the Departments of Dialysis and Nephrology at North-Estonian Medical Centre and at Linkoping University Hospital. The dialysate samples were taken and analyzed by means of UA concentration at the chemical laboratory and with a doublebeam spectrophotometer. From the calibration set of material three models for original and three for Is' derivate of UV absorbance were created. These models were tested on validation set of material and concentrations of UA from the different methods were compared regarding mean values and SD. It was found that the concentration of UA can be estimated by UV absorbance method whereby using processed UV absorbance spectra and absorbance values from several wavelengths gives better and more accurate results.