Uric acid is the major determinant of absorbance in spent dialysate allowing spectrophotometric evaluation of dialysis dose

Abstract

UV absorbance is determined mostly by uric acid. Absorbance measurements seem suitable as a method for monitoring dialysis efficiency.

Optical Estimation of Beta 2 Microglobulin during Hemodiafiltration - Does It Work?

“…3 ). This has been confirmed also by earlier studies [11,12] . Moreover, HPLC studies have demonstrated that UA is an UV-absorbing solute in the studied wavelength range, and therefore influences the UV-signal substantially [13] .…”

The Removal of β2-Microglobulin in Spent Dialysate Cannot Be Monitored by Spectrophotometric Analysis

“…Furthermore, the contribution of β2M to the absorbance was relatively less and its contribution to fluorescence was absolutely negligible. Thus, the absorbance at 280 nm is mainly due to other substances, namely, uric acid [5] . In fact, significant UV absorption and fluorescence emission signals were also measured treatments with the LF membrane, which do not allow any β2M transfer, as demonstrated by the absence 112 of β2M in spent dialysate.…”

“…An emission peak at 340 nm was observed in the fluorescence spectrum of β2M in the range 230-510 nm Toxins are removed from plasma and filtered into the spent dialysate or ultra-filtrate, via diffusion and convection, or trapped inside the membrane by adsorption. It has been already demonstrated that the analysis of spent dialysate by spectrophotometry allows the monitoring of dialysis removal of small molecules and the noninvasive assessment of dialysis efficiency and Kt/V [1][2][3][4][5] . The removal of β2-microglobulin (β2M, MW 11.8 kDa) from plasma is considered an effective marker of the dialyzer clearance for 'middle molecules' and proteins with molecular weight ranging 10-30 kDa [6] .…”

“…The sampling protocol, the analytical procedure, the instrumentation and the statistical methods have been previously described [5] .…”

Continuing education: online monitoring of haemodialysis dose

“…; Donadio et al . ), although the absorption depends on several substances with different distribution volumes and kinetics. A straight regression line can of course be drawn through almost any group of points resulting that the measurements are forced erroneously into a single pool model.…”