Validated Dried Blood Spot Analyses

In the ILERVAS cohort, a fasting dried blood spot sample was obtained by a fingertip puncture according to standard protocols. Creatinine, uric acid, and total cholesterol levels were assessed with the REFLOTRON^® Plus system (Roche Diagnostics, Germany). It is a validated clinical chemistry system with highly correlated results to well-standardized laboratory methods (21 (link)–23 (link)). The glycosylated hemoglobin test was performed using a point-of-care instrument (Cobas B101^®, Roche Diagnostics, Germany) that meets the generally accepted performance criteria for its measurement (24 (link)). In the NEFRONA cohort, biochemical parameters were obtained from a routine fasting blood test taken no more than 3 months apart from vascular examination. GFR was estimated according to international guidelines using the CKD-EPI equation in both cohorts (25 (link)).