Medical Device Mechanical Test Method Validation

[stevoc]

Hi

First post on the forum, but have been lurking for a while.

Can anyone help me please regarding Test Method Validation?

I work for a design consultancy and we've been developing a medical device for a client. We've produced devices for verification testing and will now be doing the verification testing in house.

Our client is of the opinion that we need to validate all our test methods - can anyone give me some advice on where to start please? The tests are mainly mechanical - force & torque to operate, pressure to move, sealing pressure, dose delivery accuracy etc.

How do you validate a mechanical lab test? We tried getting a series of technicians to test the same parts repeatedly, but the nature of what we are testing, means there is significant variability - so we can't show that different operators get the same results from the same test samples.

many thanks

Steve

 

[Ronen E]

Hi

First post on the forum, but have been lurking for a while.

Can anyone help me please regarding Test Method Validation?

I work for a design consultancy and we've been developing a medical device for a client. We've produced devices for verification testing and will now be doing the verification testing in house.

Our client is of the opinion that we need to validate all our test methods - can anyone give me some advice on where to start please? The tests are mainly mechanical - force & torque to operate, pressure to move, sealing pressure, dose delivery accuracy etc.

How do you validate a mechanical lab test? We tried getting a series of technicians to test the same parts repeatedly, but the nature of what we are testing, means there is significant variability - so we can't show that different operators get the same results from the same test samples.

many thanks

Steve

Hello and congrats for your 1st post

Mechanical test method validation relates closely to GR&R / MSA -- there's a lot of knowledge under this topic in the forums. Further, there's a lot of valuable guidance related to method validation in general, in the pharmacy world guidance (e.g. ICH guidelines), but you might waste (or invest?) too much time there before you find what you need. Repeating a test several times with different techs is a step in the right direction (GR&R) but I advise a bit of self-education and planning before you proceed.

The fact that results are not reproducible / repeatable is a bit alarming -- there might be a real problem with the method or/and its implementation. GR&R methodology includes tools for improving, once you've established that the results are not satisfactory.

Good luck,
Ronen.

 

[Ajit Basrur]

Welcome to the Cove, Steve

As highlighted by Ronen, Gage R & R is the right step. We have lots of attachments. Refer this to get started and pls come back if you have additional questions - Post Attachment Listing search for gr&r

 

[somashekar]

The tests are mainly mechanical - force & torque to operate, pressure to move, sealing pressure, dose delivery accuracy etc.

Your tests must show that the device performs better than the design inputs.
Your design verification must spell out where and how the requirements of the mechanical parameters must be met.
A test protocol must be made and agreed with the customer, and where instruments are used, they must be duly calibrated.
The test set up must be installed based on the protocol (IQ)
The test results must give you consistently exceeding the required mechanical requirement, over the test samples that are taken up for this activity.
Tests can be done by one qualified engineer and you are all done.

 

[Waeller]

Dear Stevoc,

what you are describing in your question is exactly what's bothering me. We are also developing test methods for medical devices which are just going into production.

So, there is not yet a stable process and further more most of these mechanical tests are destructive. We are also not able to find parts which are similar enough - because there's no test method to judge - to go for an GRR, though. Did you find some useful hints besides the provided links?

To all others,

besides pointing to a GRR is there anything else out there in the quality community which allows for judging a test method to be robust and measuring the values correctly if there are such limitations as described above?

Thanks for any hint

Waeller

 

[badgary]

If you have a lot of variation in your test method making it hard to validate and you can't reduce that anymore, but you insist your method works and can detect what it is supposed to detect, then I suggest trying an attribute type data test method validation. Your sample size will be quite significant because its an attribute test (binary results like pass/fail). The criteria to pass the test will be vague most likely due to the nature of attribute data, thus requiring a lot of samples to have any kind of confidence that your test is valid. But often when there is large variation and everything has been done to control it, you can resort to an attribute test method validation. I believe Minitab (their website) has some white papers on this subject that would be creditable. Good luck.

 

[Waeller]

Hi badgary,

thank you for your hints and ideas, this is a possible way but quite an effort.

What we are now implementing as a first guess, whether we are able to measure something reasonable, is something like the probable error approach mentioned by Wheeler.

Thanks
Waeller

 

[rajwsu]

Does a test method certification from a accreditation program can satisfy the requirements for medical device Test method validation (TMV)?

 

[Waeller]

Hi,

this might be a possible solution but who is going to check the accredited company if they are doing the right things? Just being accredited doesn't mean being perfect

Best regards
Patric