OQ instead of PQ

At what circumstances OQ considered as PQ?

I’m not sure that OQ can be considered as being PQ, but I have advised some validations stop at the OQ (testing) stage as defined by our particular validation procedures.

An example of this is our recent investment in vision systems - using cameras and associated software to pick out and reject products with certain defects. Here the validation consisted of IQ and OQ. During the OQ stage, some products were deliberately adulterated with defects which the system was designed to detect and reject. These were randomly inserted into good products and all were then inspected. The testing passed if all the adulterated products were correctly rejected. Multiple examples of each defect were inserted so that it was clear that rejecting a defective product was not a one-off event.

I don’t know whether that helps at all?


Thanks cat, it surly help, but if few more examples will be given, it will more help to me as well as our other members.

Interesting question and interesting first volley by Cat.

Do be careful, though. A PQ run over multiple shifts might reveal some issues, even with a camera system. For example, if run when lighting is different (sunshine flooding the area or lights dimmed on 2nd shift) could impact the ability of the camera to detect the defects. Also, if performed over a long stretch, dust or debris might build up on the camera lens also raising the potential that defects would be missed.

We had a case where the machinery was doing sonic welding of a plastic membrane onto a plastic part. Over time, some plastic would build up on the weld horn and not function as well. Just doing an OQ showed the device worked as required but doing the PQ showed that it could only be sustained for a few hours.

Another situation we encountered was a label printing device. It was designed to print a barcode onto a certain spot on label. Worked great in OQ tests, staying well within tolerance. On a longer PQ run, though, we started noticing the position was drifting; eventually out of range of where the camera was reading it.

So I’m not saying by any means that Cat is incorrect; just think it through. If it makes sense to not do it, be sure to document any justification / rationale for your decision.