Variation results of manufacturer COA versus results obtained in plant testing

What should be done in case variation of results in Raw material testing are observed in any of the parameter of manufacturer COA with respect to in house testing although both the test results are with in the limit, but one is on lower side and the other one is on higher side.Suggests some course of action if required.

Generally between two labs / 2 differents persons performed in same test, it should be allowed 2% variation that the results for raw material / finished / intermediates. If result obtained higher side in in house testing compared to vendor coa, to be verified both specifications limits same / different, and also considered that vendor specification having any OOT for the same, based on that investigation to be carried out. If not having any OOT, even investigation to be required to identify the obtined higher result in in house testing. Even that the result obtained lower side in in house testing, i.e. more than two % variation compared to vendor coa result, because that the root cause it might be due to laboratory, I mean column. And also in house lab to be verified and investigated that, how many batches performed earlier and trend to be verified for all the results to identity the impact. Based on out come appropriate action should be required for adequacy of investigation