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.