A practical approach to assay imprecision evaluation for clinical laboratory professionals: from concept to application

Evaluating assay imprecision is fundamental in validating and verifying analytical methods within clinical laboratories. Imprecision quantifies random variability, providing the foundation to assess analytical performance, estimate measurement uncertainty, and support reliable patient care. However, despite clear international guidance, many laboratories struggle to implement these protocols due to limited resources, statistical complexity, and varying clinical contexts. This review provides a practical framework for laboratory professionals to understand, design, perform, and interpret imprecision studies using both comprehensive analysis of variance (ANOVA) models and simplified alternatives. Rather than treating imprecision as a purely statistical exercise, we focus on translating theoretical concepts into flexible, scalable applications for laboratories with varying capacities. The article concludes with several practical core principles for modern imprecision studies.