REPORTREFERENCE OUTLINE

Out-of-Specification (OOS) Investigation Report

Two-phase OOS investigation — Phase I laboratory assessment then Phase II manufacturing investigation — driving a scientifically sound result-validity and disposition decision.

What a template is not

A template is a document baseline to adapt inside your own quality system. SPEQ does not approve, validate, or take responsibility for what you issue from it, and using one is not evidence of compliance.

CHECKING ACCESS

Checking your Professional access…

REGULATIONS MAPPED
FDA OOS Guidance (2022)21 CFR Part 211
DOCUMENT TYPE
Report
LAST UPDATED
January 2025
PURPOSE

A two-phase record that establishes whether an out-of-specification result is attributable to the laboratory or reflects the batch — laboratory assessment first, full manufacturing investigation second, with retesting controlled in between. The phase separation is the whole discipline: invalidating a result on a hypothesis that was never tested, or retesting until a passing value appears, is the failure mode this record is built to prevent.

What's Inside

OOS result identification — method, analyst, instrument, date, and the specification exceeded
Phase I laboratory investigation covering method, instrument, standards, calculation, and analyst technique
Hypothesis testing, with each assignable-cause hypothesis stated and the test that would confirm or refute it
Retest and resample plan, authorised in advance, with the number of determinations fixed before testing
Phase I conclusion — laboratory cause confirmed, or escalation to Phase II with the reason
Phase II manufacturing investigation covering batch record, process, materials, equipment, and concurrent batches
Batch impact, disposition decision and its scientific basis, plus CAPA linkage and trend review

How to Use It

1Open the record on discovery of the result, before any retest, and preserve the original preparation and data
2Complete Phase I against a written checklist; an invalidation without an identified and confirmed laboratory cause is not supportable
3State each hypothesis and the test that would refute it, then run that test — hypothesis testing is not a second analysis
4Authorise any retest or resample in advance, fixing the number of determinations before results are seen
5Escalate to Phase II whenever no laboratory cause is confirmed, and extend the scope to concurrent and prior batches
6Record the disposition and the scientific basis for it, and feed the outcome into trending so repeat patterns surface
DOCUMENT CONTENTS

The full section structure of this template — every section and sub-section, so you can use it as a baseline for your own site document.

Document Control
Document InformationApproval SignaturesRevision HistoryDistribution List
1OOS Result Identification
2Phase I — Laboratory Investigation
3Hypothesis Testing and Retest / Resample Plan
4Phase I Conclusion
5Phase II — Full-Scale Manufacturing Investigation
6Batch Impact and Disposition
7CAPA and Trending
8Approvals
REGULATORY CONTEXT

FDA's guidance on investigating out-of-specification test results for pharmaceutical production sets out the two-phase structure, the limits on retesting and resampling, and the expectation that an original result is not invalidated without a confirmed assignable laboratory cause. 21 CFR 211.192 requires any unexplained discrepancy or failure to meet specifications to be thoroughly investigated, with the investigation extending to other batches and the conclusion recorded. The disposition decision remains the quality unit's, on the evidence this record assembles.

MAPPED STANDARDS
FDA OOS Guidance (2022)21 CFR Part 211
Browse the standards catalog →