OOS Investigation Form Template (Free Printable)

In short: This is a free, printable form for recording an out-of-specification (OOS) investigation from the first suspect result to batch decision and CAPA. It has six parts (A to F) with fill-in columns. Print it, complete it in ink as the work happens, and attach the raw data. It is an example format: adapt it to your own SOP.

How to use this form

An OOS result must be investigated and the investigation written down (21 CFR 211.192). EU GMP Part I Chapter 6 §6.7 expects a procedure for investigating OOS and OOT results. FDA’s guidance, Investigating Out-of-Specification (OOS) Test Results for Pharmaceutical Production, Revision 1 (May 2022), and the MHRA Out-of-specification investigations guidance describe the phase-by-phase approach this form follows. The full explanation is in the OOS investigation complete guide.

Start the form as soon as a suspect or OOS result is seen, before test preparations are discarded. Keep stable test and standard preparations.
Complete Parts A and B first. Part B is done by the analyst and then the supervisor, before any retesting.
Do not retest until the plan in Part C is written and approved. The number of retests must be fixed in advance by your SOP, based on the variability of the method, and must not change according to the results.
If Part B finds no clear laboratory error, move to Part D (Phase II), which is led by the quality unit.
Record every result, passing and failing. Do not average the original OOS result with retest results to show compliance, and do not use an outlier test to remove a result from a validated chemical assay.
Sign and date each entry. Attach chromatograms, spectra, worksheets and instrument logs.
Keep the completed form with the batch records. Records are kept at least 1 year after the expiry date of the respective product batch (EU GMP Chapter 4 §4.11; 21 CFR 211.180(a)), or longer if local law or the marketing authorisation requires.

Further detail on each phase: Phase I (US FDA), Phase II (US FDA) and the failure investigation SOP.

Part A: Header

Item	Entry
OOS number
Date and time OOS result observed
Product / material name
Batch / lot number
Stage (raw material, in-process, finished product, stability)
Test / parameter
Method and version number
Specification / limit (with reference)
Result obtained (as reported and raw value)
Instrument / equipment ID
Analyst name
Date of analysis
Supervisor informed (name, date, time)
Quality unit informed (name, date, time)

Part B: Phase I laboratory investigation checklist

Complete before any retesting. The analyst answers first; the supervisor then checks independently.

Check	Analyst: Yes / No / NA	Supervisor: Yes / No / NA	Evidence / remarks
Was the result compared with the specification and the correct limit used?
Were the correct, current approved method and version followed?
Was the analyst trained and qualified for this method?
Are the calculations correct, with no unauthorised or unvalidated change to automated calculation settings?
Was the instrument qualified, calibrated and within its due date?
Was the instrument logbook checked for faults, maintenance or unusual events on the day?
Was system suitability performed and did it meet its criteria?
Were reference standards correct, in date and stored properly, and the standard calculation checked?
Were solvents, reagents, buffers and mobile phase correctly prepared, labelled and in date?
Was glassware clean, suitable and, where required, calibrated or verified?
Was balance use correct (calibration, daily check, weights recorded)?
Was sample preparation done as per method (weighing, dilution, extraction, filtration, sonication time)?
Was the sample correctly identified, stored and handled before analysis?
Were chromatograms, spectra and raw data examined for anything unusual (integration, extra peaks, baseline)?
Were all audit trail entries reviewed and consistent with the work done?
Were test and standard preparations retained (if stable)?
Was method performance compared with validation and historical data?
Was an obvious laboratory error found?

Phase I conclusion	Entry
Clear, documented laboratory error found? (Yes / No)
If yes, describe the error and the evidence
If no, proceed to Part C and Part D
Analyst signature / date
Supervisor signature / date

Invalidation is allowed only when a test event that can reasonably be determined to have caused the result is observed and documented. A theory such as “probably analyst error” is not enough.

Part C: Hypothesis testing and retest plan

Write and approve this plan before any retesting or re-measurement.

Item	Entry
Hypothesis being tested (for example, dilution error, instrument fault)
Reason the hypothesis is credible (evidence)
Test to be performed (re-measurement of retained preparation, retest of original sample, other)
Number of retests allowed (fixed in advance as per SOP no. ______)
Second analyst (name, experience at least equal to the first analyst)
Criteria for accepting or rejecting the hypothesis
Point at which testing stops and results are evaluated
Resampling needed? (Yes / No) and sampling procedure used
Plan prepared by (signature / date)
Plan approved by quality unit (signature / date)

Result log	Date	Analyst	Test event	Result	Within specification?
Original result
Retest 1
Retest 2
Retest 3
Resample result (if any)

Report and consider all results. Repeating tests until a passing result appears is “testing into compliance”.

Part D: Phase II full-scale investigation

Led by the quality unit when Part B shows no laboratory error and the result appears accurate.

Review item	Done: Yes / No / NA	Findings / document references
Batch manufacturing and packing records reviewed (deviations, process parameters, in-process results)
Raw material and packaging material records and test results reviewed
Equipment use, cleaning and maintenance records reviewed
Sampling procedure and sampling records reviewed (representative sample?)
Environment, utilities and water records reviewed where relevant
Personnel involved interviewed and statements recorded
Process or method changes since previous batches reviewed (change control)
History checked: previous OOS, deviations or complaints for this product and test
Other batches of the same product that may be affected (list batch numbers)
Other products made with the same materials, equipment or method
Other sites or contract manufacturer involved?
Batches already distributed assessed (list batch numbers, market)
Additional laboratory work done under the approved plan in Part C
Probable or actual root cause (describe)

Phase II conclusion	Entry
Root cause identified? (Yes / No / Inconclusive)
Summary of cause and supporting evidence
Investigation completed by (signature / date)

Part E: Conclusion and batch disposition

Item	Entry
Final classification (confirmed OOS / invalidated with documented cause / inconclusive)
Summary of all results considered
Impact on other batches and products
Batch decision (reject / release / hold / reprocess if allowed by the marketing authorisation)
Justification for the decision
Authorities to be informed (reportable?) and reference
Customers or contract givers to be informed (per quality agreement)
Quality head decision (signature / date)

Part F: CAPA and approvals

CAPA no.	Corrective / preventive action	Owner	Due date	Effectiveness check (how and when)	Status

“Retrain the analyst” alone is rarely a sufficient CAPA. See CAPA process step by step.

Approvals	Name	Signature	Date
Analyst
QC supervisor
QC head
Production head (Phase II)
QA reviewer
QA head / quality unit approval

Form closed on: __________ Cross-references (deviation no., change control no., CAPA no.): __________

Frequently asked questions

Do I fill in all parts for every OOS result?

Always complete Parts A, B and E. If Part B finds a clear, documented laboratory error and the result is invalidated, Parts C and D may be limited to the repeat test and the check that no other batch is affected, as your SOP allows. If no laboratory error is found, complete every part.

Who signs the form?

The analyst and supervisor sign Part B, the quality unit approves the plan in Part C and the conclusion in Part E, and the heads of the departments involved sign Part F. The exact signatories depend on your SOP and organisation chart.

Is this form enough to meet regulatory expectations?

It is an example format. Your own OOS SOP, your quality agreements and the regulations that apply to your markets decide what is required. Use it as a starting structure and align the wording and number of retests with your approved procedure.

References

US FDA, Guidance for Industry: Investigating Out-of-Specification (OOS) Test Results for Pharmaceutical Production, Revision 1, May 2022 (CDER). fda.gov/media/158416/download.
US FDA, 21 CFR 211.192, Production record review. ecfr.gov.
US FDA, 21 CFR 211.180(a), General requirements for records. ecfr.gov.
MHRA, Out-of-specification investigations, GOV.UK, published 28 August 2013, updated 26 February 2018. gov.uk/government/publications/out-of-specification-investigations.
European Commission, EudraLex Volume 4, EU GMP Part I Chapter 6: Quality Control (in operation from 1 October 2014), §6.7.
European Commission, EudraLex Volume 4, EU GMP Part I Chapter 4: Documentation, §4.11.