OOS investigation

Dear experts, in key starting material OOS investigation, if not identified assignabl root cause during investigation, reanalysis with resampling is possible / not as per regulatory guidelines, for that any guidelines mentioned specifically.

No need of re-sampling for API Starting Material, if investigation team felt there is a need of re-sampling with some sort of suspection.

go with your approved SOP and applicable guidances. In general it is not required but companies do practice of extending the investigation to vendor if assignable root cause is not identified in QC lab. further some companies they do Phase 2 investigation by performing re-analysis with different analyst. It depends on companies policy of handling OOS.

If the assignable root cause is not identified then following actions can be taken
Perform additional hypothesis testing
Initiate extended investigation including phase 2 investigation
Perform duplicate testing with Analyst 1 and 2