Assay Validation Risks and Challenges

Assay validation is a complex activity with many independent variables that may affect data integrity, regulatory acceptance, and ultimately the reliability of clinical or product-quality decisions.  It is important to source proper materials and reagents because inaccurate reference standards, poorly characterised materials, or incorrect calibration curve fit may cause the regulator agency to reject the assay for its intended purpose. During validation, scientists often run into poor precision issues such as high intra-run or inter-run variability, due to reagent lot differences, instrument drift, and operator error.  These challenges must be controlled as much as possible by proper training, securing bulk reagent supplies and vendor quality agreements. Additional challenges may arise due to sample cross-reactivity (especially in ligand-binding assays), high background noise, and poor signal-to-noise due to sample matrix complexity.  Importantly, data integrity is imperative for assay validations that must align with FDA expectations.  The code of federal regulations 21 CFR Part 11 requires that electronically stored data must be trustworthy, reliable, and equivalent to paper records. This code governs all electronic records, electronic signatures, audit trails, and computerised system controls used for FDA regulated activities. Assays intended for use in FDA inspected facilities will need to be validated using equipment and devices with 21 CFR part 11 compliant software. Audit trails must be secure, and time stamped showing history of creation and use. Access controls must be password protected with permissions settings and signatures. The computer system used to create and maintain the data must be validated. This aspect of assay validation becomes particularly challenging because of the time and resources needed for compliance. Small biotech companies can efficiently comply with 21 CFR Part 11 by taking a risk-based, software-assisted, and streamlined documentation approach. Prioritize high-risk systems, leverage compliant commercial software, validate intelligently, and maintain concise SOPs with role-specific training.