Measuring Instruments - Should/Must Be Calibrated BEFORE and AFTER Qualification/Validation Tests?

Dear colleagues,

Could you please, share your experience or point of view.

During qualification activities IQ/OQ/PQ we use external measuring instruments (devices) - for example, thermocouples. This external instruments must be calibrated before we start Q-tests. Is it obligatory/recommended to perform (re)calibration after tests?

Thank you in advance for your opinions!

The instrument should be calibrated before use and certainly have an IOQ. Unless you really want to recall your manufactured lots.

Dear Boomer_Chemist thank you for your input. This is very clear, for sure all measuring instruments are calibrated.
May be my explanation was little bit confusing. For now we are in the process of PQ for autoclave. During qualification of each load we use external temperature sensors.For sure, all used sensors are calibrated according to the specific requirements. We check calibration certificates prior to do any tests. Should we perform calibration after all tests (there are 6 or 7 different loads and tests will take time) or at the end of PQ we just should verify that period of calibration is not exceeded?

You need to do pre calibration for sure that you know the deviation of thermocouple. And after you complete the qualification you should do post calibration for verification. And do this in a cycle. So you must record the deviation before and after. And do it with an integrated system. AVS Kaye have this system for thermal validation.

Calibration is not necessary afterwards. As part of your PQ you can evaluate your sterilization effectiveness (as long as the OQ has not revealed any cold spots). Sterilization effectiveness means your looking at your loading patterns and cold spots between the boxes/lots (remember it is the mass of the load that is involved). Then as your ongoing monitoring program you can use results from a calibrated chart recorder.

You should use both calibrated thermocouples and BI indicators in your PQ.

You do not NEED to calibrate before each load. Calibrating before the Qualification and after the end of the qualification is sufficient. That being said, Thermocouples are fragile and can break. For this reason you need to write in a clause which states what your action plan will be in the case of a TC failure or breakage.

Running a calibrating-verification regularly (maybe every 3 runs, maybe every 5 runs) is a good way to mitigate the risk of a Thermocouple (TC) failing. You can also have a statement that 1 TC may fail every without impact to qualification, or maybe 10% of TCs may fail without an impact.

So I would do runs like this
Engineering studies - just calibration and run until one fails. Then stop using that TC for a while.

Qualification Studies
calibration verification (don’t recalibrate here)
Change loads -
calibration verification (again done recalibrate)
Change loads.

WIth the above, you only risk “losing” runs between calibration verifications.

If the TC’s start to get worn, then do a calibration verification, then do a calibration, then do your runs.

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Thanks a lot!