First, let me make two points. One, the FDA says that the testing used must be “scientifically valid”—one of the few places in the CFR regulations where validation is used. Second, whatever you choose to do for testing (and the FDA leaves quite a bit of leeway here) must be defensible to the FDA auditor.  You should keep those points in mind when designing your testing plan. So let’s take your proposal step by step.

The first part of your question seems to say that you want to use outside lab data in order to qualify an in-house reference standard that will be used for identity testing via FTNIR. This would certainly be allowable. Creating in-house reference standards is a common practice. You may choose to get multiple analyses done in order to qualify that standard and that would be recommended.

The second part of your question involves preparing a COA. You certainly could use your qualified in-house reference standard in your identity test method and report those results on a COA for your product. Your identity test method would need to be validated for the type of blend you are producing.