During laboratory testing, certain results may be flagged for further review to ensure accuracy and reliability. These flags—Atypical, Out-of-Trend (OOT), and Out-of-Specification (OOS)—help identify results that differ from expected patterns or customer-defined specifications.

This article explains what each classification means, why it might be triggered, and what actions AsureQuality and customers may need to take. To support understanding, we’ve included a diagram showing the full testing process—from sample dispatch to the delivery of the Certificate of Analysis (COA)—and where these classifications fit within it.

1. Atypical

Situation:
Used by a Key Technical Person (KTP) in reference to results from a test during the "result verification" step in the testing process. 

Definition:
An unauthorised result that has had an anomaly during the quality checks or observation that is unusual, unexpected, or inconsistent with prior experience for that sample type or matrix. It often prompts further investigation or confirmation, but does not inherently invalidate the original result.

Common triggers for use:

• The result doesn’t match usual patterns or expectations.
• The analyte shows interference or deviates in trend.
• Colony morphology or instrument readings differ from norms.

What next?

AsureQuality actions:

• AsureQuality to investigate further; a delay notification will be sent to advise of the potential delay to the expected reporting date. Further investigation could involve retesting the sample and/or having a senior scientist review the result and testing data.
• AsureQuality may contact the customer directly to discuss the result and ascertain if the variation is expected.
   

Customer actions:

• Alert the product release/logistics teams to the potential delay.

2. Out-of-Trend (OOT)

Situation:
Used by a Key Technical Person (KTP) in reference to results from a test during the "result verification" step in the testing process. 

Definition:
An unauthorised result that deviates significantly from historical or contextual trends for that sample type, batch, or project, despite possibly still being within customer specification limits.

Common triggers for use:

• Outlier within a batch or series (e.g., 1 result out of 5 differs significantly).
• Contradicts established historical data or the expected range.
• Significant deviation from control or comparative samples.
• Often prompts retesting or additional verification.

What next?

AsureQuality actions:

• AsureQuality will investigate further; a delay notification will be sent to advise of the potential delay to the expected reporting date. Further investigation could involve retesting the sample and/or having a senior scientist review the result and testing data.
• AsureQuality may contact the customer directly to discuss the result and ascertain if the variation is expected.
   

Customer actions:

• Alert the product release/logistics teams to the potential delay.

3. Out of Specification (OOS)

Situation:
A flag/classification against a result that is triggered automatically by the AsureQuality LIM system in response to authorised results that do not meet the customer's acceptance criteria as recorded on their specification. Results are only authorised AFTER all quality checks and verification steps have been completed. 

Definition:
An authorised result that has met all quality checks and falls outside of the specification limits provided by the customer, often triggering a formal deviation process, investigation, or retesting in regulated contexts (e.g., GMP).

Common triggers for use:

• The measured result is above or below the customer-defined limits.
• May require formal reporting, especially in pharmaceutical or GMP settings.
• Result highlighted in LabConnect for customer attention.

What next?

AsureQuality actions:

• Upon authorisation of results by the KTP the LIM system checks the results against the customer specifications. If the result is outside the acceptance criteria of that specification an automated OOS notification is sent to a predetermined set of recipients.
• AsureQuality has now completed the laboratory testing, all quality controls have been met, and we are confident in the result being reported.
   

Customer actions:

• Customer to trigger any OOS processes as necessary for their business.
• The customer may request a "retest" of a fresh sample for comparison (fees apply if results are reproducible with the original).
• The customer may request an OOS investigation report to be completed (a fee applies per OOS Investigation).