A Targeted LC-MS/MS Assay of a Health Surveillance Panel and Its Application to Chronic Kidney Disease

Robust and reproducible assays capable of specific and quantitative monitoring of multiple biologically important proteins, among the thousands of human plasma proteins, can be used to represent the overall health of an individual and distinguish health versus disease. In this study, we established an LC-MS assay to monitor a Health Surveillance Panel (HSP), comprising 60 circulating plasma proteins selected based on their biological functions and/or disease associations. Plasma samples were prepared for proteomic analysis in an automated process and analyzed using an optimized, scheduled LC-MRM assay composed of 60 endogenous proteins monitored by 364 transitions from 117 proteotypic peptides, along with their stable isotopically labeled standard peptides. For each proteotypic peptide, a quantifier ion and at least two qualifier ions were selected based on consistent peak area ratios, a linear response for the quantifier ion, and a low limit of quantification. As proof of concept, we evaluated the performance of our HSP assay in a case-control study of progressive chronic kidney disease (CKD). Reduced plasma concentrations of alpha-2-antiplasmin, antithrombin-III, and immunoglobulin heavy constant alpha 1 correlated with CKD, with p-values <0.05. These results demonstrate that CKD-associated differences can be detected with a multiplexed HSP assay panel.