Application of ES-DMA-CPC for Comprehensive Molecular Profiling in Hemodialysis: A Focus on β2-Microglobulin

Accumulation of middle- and large-sized uremic toxins has been associated with frailty and mortality in hemodialysis patients. In clinical practice, immunological methods are used for the quantification of those toxins; however, the requirement for expensive antibodies and chemicals limits their clinical application. In this study, we propose an antibody-free analytical method, an electrospray differential mobility analyzer coupled with a condensation particle counter (ES-DMA-CPC), for the analysis of middle- and large-sized uremic toxins in spent dialysate collected from hemodialysis patients. When applied to the analysis of the middle-sized uremic toxin β2-microglobulin, the spent dialysate-based ES-DMA-CPC method shows a high correlation with the current gold standard, enzyme-linked immunosorbent assay, as well as the serum-based immunoturbidimetry. Additionally, ES-DMS-CPC simultaneously provides concentrations of molecules with a molecular weight range of 2.5-180 kDa, which offers possibilities for the study of the molecular profile in hemodialysis patients and for the quantification of the practical sieving performance of the dialyzer.