In a laboratory environment, the handling of Out of Specification (OOS) test results can be challenging. It can be difficult to determine if the OOS result is valid or if retesting is appropriate and can be justified. One way to approach this, is to conduct an OOS Investigation.

This White Paper provides an example OOS Investigation Checklist, as well as a discussion on OOS Investigation, including:

• What is an OOS Investigation?
• When is an OOS Investigation appropriate?
• What should an OOS Investigation include?
• How can an OOS Investigation result justify retesting?