Out-of-specification (OOS) investigation process

What the out-of-specification (oos) investigation process process is

The chart preserves the original data and sample, tests whether evidence supports an assignable laboratory cause, then expands the investigation and impact assessment where the result remains valid. It is deliberately a starting point: adapt the roles, criteria, records and escalation thresholds to the services and risks your laboratory actually manages.

The meaningful branches are not footnotes. Data and samples secured?, Obvious assignable laboratory cause? and Original result invalidated by evidence? decide whether routine work can proceed or whether the laboratory must hold, clarify, investigate or escalate the work.

This template does not establish compliance with any standard or regulation. Confirm the procedure, safety controls, authorization roles and retention requirements that apply at your site before making it effective.

What this flowchart covers

In this template

• Five stages from secure evidence through close across the roles that own this workflow.
• A documented positive and negative path for data and samples secured?, so an exception stays visible rather than disappearing from the flow.
• The obvious assignable laboratory cause? gate before routine work continues, with a hold, investigation or remediation path where it does not.
• A final original result invalidated by evidence? decision that routes both outcomes through controlled records and closure.
• Editable swimlanes and labels that can be aligned with the laboratory's approved methods, local forms and quality-system terminology.

When to use this template

• You need a high-level OOS decision tree that prevents testing into compliance while remaining adaptable to your product, method, quality system and governing requirements.
• You are revising an SOP, training material or audit-ready process map and need the failure paths visible alongside the routine path.
• Several teams own parts of the workflow and need a shared view of the handoffs, evidence and escalation points.

How it works

1. Set the real roles and records

   Replace the example lanes with the people who actually perform Analyst / Technician, Laboratory Supervisor, Quality Assurance. Add the SOP, form, system or logbook that provides evidence at each handoff.

2. Define the decision criteria

   Write the site-specific rule behind each decision, especially data and samples secured?, obvious assignable laboratory cause? and original result invalidated by evidence?. Do not leave a result-dependent decision to informal judgement.

3. Test the exception paths

   Walk a recent non-routine case through the hold, clarification, investigation or remediation branches. Change the chart wherever the real response differs from the draft.

4. Approve and review the procedure

   Route the completed process through your document-control and approval process, train the affected roles and review it when methods, systems, responsibilities or risks change.

Frequently asked questions

What does this out-of-specification (oos) investigation process cover?

The chart preserves the original data and sample, tests whether evidence supports an assignable laboratory cause, then expands the investigation and impact assessment where the result remains valid. It includes the decision points and exception routes needed to prevent a failed check or unclear handoff from being treated as routine work.

Can this template be used in a regulated laboratory?

It is an editable starting point, not a compliance claim. Regulated and accredited laboratories should align the roles, records, acceptance criteria, method controls and approvals to their applicable framework and approved quality system.

How should we adapt the workflow?

Start with the actual records and roles used at the site, define the criteria behind each decision, then test the exception branches against a recent real case. Remove steps that do not occur and add required local controls before approval.