1 Changes to the product that could affect method performance (e.g., formulation excipients, product concentration)
2 Changes in critical assay reagents that cannot meet prior specifications (e.g., gel or blot materials, enzymes)
3 Changes in instrumentation that cannot perform equivalent procedures (e.g., hydrolysis systems)
4 Changes in the procedure to improve robustness of the method (e.g., new qualification procedures for critical reagents, re-optimized sample preparation steps)
5 Changes in the product specifications that go beyond the capabilities of the test method (e.g., specification on quantifying impurities drops from 0.5% to 0.1%; assay limit of quantitation is 0.25%)
Table 9: Potential triggers for method revalidation.