Aldosterone measurement
Tecan
Collected blood samples were centrifuged at 2000 g and 10 °C for 10 min and serum probes were stored at − 80 °C until evaluation. Serum aldosterone concentrations were determined twice according to the manufacture’s protocol using the ELISA kit (RE52301) from Tecan (Männedorf, Switzerland). The optical density of the samples and standard solutions used as references were measured at 450 nm. Quantified absorption levels were averaged and standard curves were calculated using a four-parameter logistic curve fit with the freely available AssayFit Pro add-in (Version 1.41, Nijmegen, Netherlands) for Microsoft Excel.