Missed Quarterly Dose Audit! Sterilization Validation of Medical Devices


Laura Halper

Hi Tara,
I'd like to weight in with Jimmy on this one. There is a big difference between not doing any dose audits for 2 years and having records showing quarterly dose audits have been done on a regular basis with one slip up where it was missed.

Also, note that EVEN IF a quarterly dose audit fails, ANSI/AAMI/ISO 11137-2 allows you to simply augment the sterilization dose, or take corrective action if there was a bioburden spike and then revalidate. The standard does not state that you must call into question the sterility of the product sterilized since your last passed dose audit. It's my understanding that this is because the establishment of the sterilization dose incorporates a large safety margin beyond the verification dose. I have seen where companies have had to augment a dose, and the FDA did not raise any questions when this was reviewed during routine inspection.

In your case, you did not fail a quarterly dose audit, and you have data to support a position that bioburden has been under control, even though not tested on schedule.

That's my view,


I posed this scenario to our consultant since we could potentially be in the same position. Our consultant is ex-FDA national medical device expert and said that if we were able to demonstrate no changes to the process (including no changes in bioburden) and document the investigation in our CAPA process, then there would be no grounds for a recall.
Hi, related to this dose audit, let me say im working in a R&D company and we have a contracted supplier that do the sterilization for our samples to be use in clinical trials. As as customer, are we the one who is responsible to do the quarterly dose audit in our sterilization process supplier as per ISO 11137-1?
or requiring our supplier to send to us the quarterly dose audit report will be enough?
I am working with a Quality consultant and that what they told us to do but for me it seems overdoing as we do not have sterilization process instead we got a supplier to do that for us. Any thoughts? comments?

if you are the legal manufacturer of the device, then you are responsible for all manufacturing processes, including outsourced sterilization processes. So yes, you do have a sterilization process.

The responsibility of the contract sterilizer is typically limited to
- qualifying and maintaining the equipment
- process your products according to the parameters you have to provide, be it validation or routine runs

In practice, sterilization contractors do have the expertise how to correctly validate and how to routinely run sterilization processes and can provide advice and appropriate documentation.

This all should be settled in a quality agreement between you and the sterilization facility. The contractor will typically provide you with a template on request.

A note on validation / dose audit frequency in case you manufacture only a few products, which might be the case for a clinical trial:
You only have to perform a dose audit in the quarter you are actually producing products. In case you are producing only a few products in a single batch, you can reduce your validation effort by making use of e.g. ISO 11137-2:2012, section 9.3, "Procedure for Method VDmax25 for a single production batch"



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