Legacy Systems and Retrospective Validation
Retrospective validation is defined by the FDAas validation of a process for a productalreadyin distribution based uponaccumulated production, testing, and controldata.As prescribed by the FDA, there are two ways toretrospectively validate an existing system: Existing historical data can be utilized if it isaccepted that the system has not changedover time and/or the system can be tested against newprotocols for all functions that have a directimpact on product quality.
When existing or legacy computer systems are used in FDA or equivalent international environments they should be validated, a process sometimes called retrospective validation. While the industry is very well familiar with the validation of new systems, there are many questions about existing or legacy systems. Application of the principles of validation to legacy computerised systems. How to demonstrate that an existing system is fit for purpose, and how and what to test during retrospective validation.
