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

Thursday, 3 September 2026 9 .00 - 17.00 h
Establishment, Use and Maintenance of Analytical Reference Substances
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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