Validated low-volume aldosterone immunoassay tailored to GCLP-compliant investigations in small sample volumes

Abstract

IntroductionHeart failure is well investigated in adults, but data in children is lacking. To overcome this shortage of reliable data, appropriate bioanalytical assays are required. ObjectivesDevelopment and validation of a bioanalytical assay for the determination of aldosterone concentrations in small sample volumes applicable to clinical studies under Good Clinical Laboratory Practice. MethodsAn immunoassay was developed based on a commercially available enzyme-linked immunosorbent assay and validated according to current bioanalytical guidelines of the European Medicines Agency (EMA) and U.S. Food and Drug Administration (FDA). ResultsThe assay (range 31.3–1000pg/mL [86.9–2775 pmol/L]) is characterized by a between-run accuracy from − 3.8% to − 0.8% and a between-run imprecision ranging from 4.9% to 8.9% (coefficient of variation). For within-run accuracy, the relative error was between − 11.1% and + 9.0%, while within-run imprecision ranged from 1.2% to 11.8% (CV). For parallelism and dilutional linearity, the relative error of back-calculated concentrations varied from − 14.1% to + 8.4% and from − 7.4% to + 10.5%, respectively. ConclusionsThe immunoassay is compliant with the bioanalytical guidelines of the EMA and FDA and allows accurate and precise aldosterone determinations. As the assay can run low-volume samples of 40 μL, it is especially valuable for pediatric investigations.