Glossary
Out-of-Specification (OOS) Result
A test result that falls outside the specification or acceptance criteria in the marketing application, the pharmacopoeia, or the manufacturer's own standard.
Details
An OOS is a test result outside specification, and the original result cannot be invalidated on the hypothesis of laboratory error alone. Inspections cite retesting without a scientific hypothesis, selection of the favourable result, and investigations not extended to the manufacturing process or to other batches. Check the raw data and audit trail, the calculations and the state of the equipment, the phased OOS investigation, the batch impact assessment, and CAPA.
Related sections
21 CFR 211.160–211.194EU GMP Part I Chapter 6
Related terms
Real inspection findings
Findings from regulators' inspection documents in which this term appears.
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For example, our investigators observed partially completed and torn-up manufacturing records for a lot of children’s acetaminophen and stacks of loose printed…
FDA · FDA Warning Letter · 2023-09-12 -
Deficiencies were also raised in the management of documentation, traceability of GMP activities, deviations, OOS.
EMA · EU GMP NCR (EudraGMDP) · 2025-12-04 -
Regarding your failure to conduct adequate investigations, our comprehensive review of your firm’s multiple deviation reports and SOPs reveals significant deficiencies in documentation and execution procedures for out-of-specification (OOS) events and deviation investigations.
FDA · FDA Warning Letter · 2026-05-12
