Medical Device Test Systems
In our 25 years of being a systems integrator, developing automated systems for the biomedical and biotechnology industry, we have learned some guiding principles.
It’s a good idea to test anything you build to ensure it is working. In the medical device industry, it’s not only a good idea, it is required per FDA regulations. Automated testing has several advantages, including reliability, repeatability, and in most cases huge cost savings. It can often increase manufacturing capacity, too.
As one indication of how critical test systems are to the overall process, test systems must pass rigorous and thorough documented procedures, much like that of the devices themselves. While the test system doesn’t have to go through clinical trials, it does have to meet verification and validation criteria. Thus, it is important to consider the test system in the overall context, and this is best accomplished with a systems engineering approach.
The goal of verification is to prove that the device built is the one that was designed. Likewise, test system verification is proving that the resulting system matches the design. Similarly, validation is proving that the device / test system built meets the original specification. So, it is important for whomever is building the test system to have an understanding and experience executing verification and validation of test systems.
However, automated test is not just for production testing. It can be used to great effectiveness in R&D as well. For example, you are designing your next generation implantable device. There are multiple design goals for the device, including low power use, reliable operation, and increasingly, programmable operating modes and parameters. Note that reliable operation is not just the ideal case, but includes potential failure modes as well. For example, does the device do the right thing when it’s power source is running low? Does it fail as safely as possible if something goes wrong, like the complete loss of power? Automation also facilitates repetitious testing, which is often required to prove all requirements have been met, and that the performance of the device is stable. These goals and criteria can be measured and tested with an automated test system.
Automating test and measurement aids repeatability of the results. As you make changes to the device design, the test system can provide stimuli, and measure responses in essentially identical ways. Thus, any changes in results can be attributed to the changes in the device, instead of incidental changes in the testing. Also, an automated test system can do testing faster, so you can have more test cases, and perform the testing quicker. In cases of very repetitive tests, which are notoriously difficult for humans, an automated test system can perform the one thousandth test identically to the first. And it can run 168 hours per week, instead of just 40.
Many of the same principles apply to an R&D test system, although typically less stringently. You still want to be sure that you built the right system (validation), and you built it the right way (verification). Because the R&D test system is not involved in the final pass / fail decision of the manufactured device, the paperwork burden is less. However, it is still important to understand and apply these good design practices.