Urinary and plasma creatinine, albumin, and protein were measured using Siemens Flex reagent cartridges for the respective proteins, while electrolytes were measured using a Siemens V-Lyte integrated multisensor and all read using a Siemens Dimension Vista 1500 chemistry analyzer at Hunter Area Pathology Service (Newcastle, NSW, Australia).
Plasma cystatin C was measured at Pathology New England (Tamworth, NSW, Australia) using a Gentian Cystatin C Immunoassay read on a Beckman Coulter DxC 600 analyzer.
Commercially available enzyme-linked immunosorbent assay (ELISA) kits were used to measure plasma and urinary prorenin (Molecular Innovations, MI), ACE (Duoset, R&D systems, MN), and AGT (IBL International, Hamburg, Germany) according to the manufacturer’s instructions (see also [Sykes et al. 2014a (link),b (link)]). The intra- and interassay coefficient of variation (CV) for each assay was 26.5% and 16.9% (n = 2 plates) for ACE, 7.7% and 7.9% (n = 2 plates) for AGT, respectively. The intra-assay CV for the prorenin assay was 17.1%. The lowest values we could successfully measure for uACE, uAGT, and uprorenin were 0.001 ng/mL, 0.2 ng/mL, and 0.6 pg/mL, respectively.
Plasma cystatin C was measured at Pathology New England (Tamworth, NSW, Australia) using a Gentian Cystatin C Immunoassay read on a Beckman Coulter DxC 600 analyzer.
Commercially available enzyme-linked immunosorbent assay (ELISA) kits were used to measure plasma and urinary prorenin (Molecular Innovations, MI), ACE (Duoset, R&D systems, MN), and AGT (IBL International, Hamburg, Germany) according to the manufacturer’s instructions (see also [Sykes et al. 2014a (link),b (link)]). The intra- and interassay coefficient of variation (CV) for each assay was 26.5% and 16.9% (n = 2 plates) for ACE, 7.7% and 7.9% (n = 2 plates) for AGT, respectively. The intra-assay CV for the prorenin assay was 17.1%. The lowest values we could successfully measure for uACE, uAGT, and uprorenin were 0.001 ng/mL, 0.2 ng/mL, and 0.6 pg/mL, respectively.