What Happens When You Can’t Test a Test?

Posted on April 16, 2013

Test Method Validation (TMV) is a critical part of ensuring quality for manufacturing. This highly specific aspect of validation involves proving that quality testing procedures for a manufacturing process consistently provide accurate results. When a TMV fails, specific steps must be taken, in the proper order, to ensure the best remediation and damage control possible.

The first order of business is to thoroughly examine the reasoning behind the Test Method. Why is it done? Does a risk assessment identify the need for a Test Method? Is there a regulatory requirement that is satisfied by this test? It’s quite possible that the test is, in fact, no longer needed; many tests are kept in place as added precautions, but historical changes to procedures and configuration have rendered them meaningless. In some cases, regulations will change and cause a test to no longer be required. We recently encountered an example of this at a medical device facility. Electrical leakage testing had been instated quite some time ago for a patient implanted medical device containing sensors. Later, an isolating unit was included in the implant configuration, thus protecting the patient from AC current and rendering the electrical leakage testing unnecessary. However, the test had been continued for various reasons. When the TMV was executed, the test failed. In a case like this, it might be determined acceptable to discontinue the failed Test Method. If this route is taken, it may be necessary to revise information submitted to the FDA regarding the device. If the Test Method is deemed to no longer be necessary, but the manufacturer decides to continue to perform the test anyway, the Test Method must still be modified so that it can be validated. The manufacturer must also ensure that performing the revised, validated method does not add risk to the product.

On the other hand, it may be determined that the Test Method is quite necessary. In this case, the first step is to examine the TMV protocol. Were there any steps built into this protocol that cause it to fail? It may be the case that some aspect of the validation itself is causing a failure by interfering with the test being performed. Are the samples used during testing representative of the product? Does the validation use a good representation of the live production environment? If one of these checks reveals a flaw in the validation methods being used, the validation can then be revised with additional controls and procedural changes, and then be re-executed. However, if none of the scenarios laid out above are determined to cause the TMV to fail, it is important to identify the causes of failure in the test itself, modify the test so that is will pass validation, and initiate damage control.

Determining the effect an inaccurate test has on a product is key at this point. If products have historically been deemed sound based on the results of the failed test, it may be necessary to recall product that has already been distributed.

The most important thing to focus on during the entire process is root cause. Why is the test done? What has changed since it was first instated? What does it affect if it fails? Quality testing is a tricky and intricate business. Why should validating the effectiveness of such efforts be any different? When Globiox consults on a project like this, we take a pragmatic, stepwise approach to remedy any issues encountered along the way.  If you want to know more Contact Us. Comment on our blog and join the conversation.

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