OOS Results - Very helpful Q&As published on the MHRA Website

Recommendation
11-13 June 2025
Development, Validation & Control
The FDA Guidance on OOS Results from 2006 is well known among the pharmaceutical industry. Guidance from the MHRA on how to handle out-of-specification results during laboratory analysis is - on the contrary - pretty unknown although an own webpage on the MHRA website is dedicated to the OOS topic.
This webpage lists 20 questions. Here are some of the topics dealt with:
- When is it acceptable to declare test results invalid?
- How many repeat tests should be conducted?
- Can OOS results and pass results be combined?
- How the certifying QP should handle unclear results
- Averaging of separate test results
- Retesting
- Re-sampling
- Outlier tests
To read all the 20 questions and answers please see "Out of specification (OOS) FAQs".
On the MHRA website, you can find a complete presentation on Out Of Specification Investigations. The presentation ends with the following statement: "Microbiological expectations will be provided at a later date."
At ECA's OOS Forum on 19/20 June 2012 in Prague, Di Morris, GMP Inspector for Medicines and Healthcare products, MHRA, UK, will give a presentation about "OOS in Microbiology". For the first time ever, she will present the requirements of a European authority regarding the GMP-compliant handling of OOS results in the microbiological laboratory.
Author:
Dr Günter Brendelberger
CONCEPT HEIDELBERG (a service provider entrusted by the ECA Foundation)
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