The term “out-of-tolerance” (OOT) is used in a number pharma quality control lab to characterize circumstances in which a process or product fails to meet its defined specifications. An OOT can occur for a number of reasons, but in order to stop it from happening again, it is possible to identify and treat several frequent root causes. We’ll will list some of the most likely OOT root causes in this post.
The following are typical possible sources and mechanisms for OOT events that may occur during stability evaluation:
Sample Related
- Sample selection and sample handling errors
- Drift in standards or reference materials
- Stability of test samples or critical reagents
- Sample materials and plate errors
- Expiry of bulk materials, Samples and Reference standards
- Vendor and lot variation on critical reagents
Analysis and Instrument Related
- Dilution and sample-preparation errors
- Temperature, reaction time, and pH effects errors
- Flow rates and process time errors
- Analyst errors
- Nonstandard test procedures and not following the method standard operating procedure (SOP)
- Calibration or compensation errors
- Interaction and composite errors.
