A quality control system for ligand-binding assay of plasma renin activity: Proof-of-concept within a pharmacodynamic study

While the role of plasma renin activity (PRA) in heart failure has been widely studied in adults, comprehensive data on pediatric heart failure remain lacking. This drawback is increasingly being addressed by academic research. Nevertheless, such pediatric investigations are commonly conducted only once due to ethical constraints. Therefore, the quality of bioanalytical data must be ensured to acquire meaningful insights into maturing humoral parameters. However, appropriate post-validation assessment of bioanalytical runs is currently underrepresented by regulatory guidance. Thus, for applications in an academic environment, an easy-to-handle six-step bioanalytical quality control system was designed based on regulatory guidelines (e.g. U.S. Food and Drug Administration) combined with international recommendations (e.g. Clinical and Laboratory Standards Institute) and current scientific discussion. Its applicability to an enzyme-linked immunosorbent assay for determination of PRA was investigated within three pediatric trials of the EU-funded "Labeling of Enalapril in Neonates up to Adolescents" project. This quality control system identified 15 % bioanalytical runs as non-compliant to the predefined specifications and ensured the reliable quantification of 940 pharmacodynamic samples. The inter-run assessment of quality controls was able to demonstrate the comparability of the study results. Furthermore, 86 % of incurred sample reanalysis pairs complied with regulatory requirements (>67 %), thus underlining the long-term reproducibility of the utilized ligand-binding assay. Successful participation in interlaboratory testing confirmed the accuracy of the applied method throughout the entire study period. Further investigations showed no notable differences between the five applied lots of the PRA assay. The applicability of this quality control system was proven in an academic environment and ensured reliable results for PRA over the entire 24-month study period.