Disposable medical devices require stringent leak and blockage testing to ensure proper clinical functionality. Developing a testing process for testing disposable medical devices depends on many variables, including the type of part and its functionality requirements during actual use.
With over 40 years’ experience, CTS has helped medical manufacturers across the globe develop their testing processes for a wide variety of medical devices on their production lines. We’ve worked with many different kinds of disposable medical devices, including balloon catheters, multi-lumen catheters, vascular access sheaths, microfluidic chips, reagent cartridges, medical solution and blood bags, cannula and flow regulation devices, check valves, tubing sets, respiratory breathing tubes/circuits, endoscopy trocars/ports, surgical tools, and more.
There are many considerations when developing a test process for a new disposable medical device in your product line. See the below questions you should consider, including how to identify potential failure points, identifying the best test methods and tools, and what to ask your solution or equipment supplier.
Identifying your potential failure points for testing
The first thing you’ll do when developing a testing process for a new medical device is to ask yourself, “What could go wrong?”. Considering what could possibly go wrong in clinical use helps to reveal all the areas you’ll want to test for in your process. Ask yourself the below questions to help identify failure points, highlighting what we need to or want to detect in the new test process.
LEAK TESTING
1. What is your media in clinical use? Semi-solid (paste/tissue), liquid (solution, blood, drug), gas (air, vacuum, oxygen, anesthesia, CO2)
2. What happens if that media leaks? Is the media biohazardous? Radioactive?
3. What happens if there is exposure to air or other media? Risk of an embolism or air bubble in a blood pathway? Bio-contamination of a sample, perhaps in IV diagnostic use?
4. What areas of the part could have leaks following an assembly error? Solvent bonding/UV adhesive connections? Weld joints?
BLOCKAGE TESTING
5. Is there a pathway for your media to transfer through within the device when in clinical use? Does it go all the way through the device (inlet to outlet)? Does it only go to a closed reservoir or termination point?
6. What happens if that pathway has blockage? What happens if the path is completely blocked? What if it’s only partially blocked?
OTHER TESTS
7. Are there any other functional aspects to consider? Does functioning rely on the opening of a check or pressure relief valve that needs to be tested? Either pressure or vacuum that the part is supposed to generate, and do we need to test to confirm this? Seal strength/structural integrity testing required?
Determining the best test method for your application
When identifying which test method is best for your new testing application, there are many considerations. We need to ask ourselves how to test the parts to challenge the above potential problems/failures possible in the part—how to test them to confirm these problems won’t happen during use by a caregiver.
Most often, these test methods will include pressure decay or vacuum decay for leak testing as well as blockage testing.
LEAK TESTING
1. What is the typical operating pressure in clinical use?
2. What is the peak (worst-case) pressure the device may see during use?
3. Do I have a spec already in place for the same or similar parts that I could use as a starting standard for this new device?
4. Do I want to determine what causes a clinical failure and reject some fraction of that? (with empirical study)
5. Do I want to determine what is the “typical” acceptable range for ‘pass’ devices, and reject anything that does not fall into that normal range? (without empirical study)
BLOCKAGE TESTING
6. What is the typical operating pressure in use and is it critical to test at that specific pressure?
7. Do I have a spec already in place for the same or similar parts?
8. Do I need to detect complete/total blockages only (attribute) or partial blockages (grading)?
OTHER TESTS
9. What are the specs for the opening pressure for the check/pressure relief valve and do those need to be verified? Do I need to know precisely what pressure the valve opened? 10. Do I need to check for leakage in back-flow/reflux conditions?
11. What seal strength must this device have?
Selecting the best tool(s) for your application
Once you’ve defined which method you should use for your testing, you’ll need to decide on the tools, or instruments. You’ll want to consider the practical abilities you’ll want a solution to have, as well as how you may want to expand a solution in the future. The below questions will help you in selecting the right test equipment and mating connections for your application.
GENERAL
1. Will I need to test 100% of my products produced or instead only an audit/sampling exercise?
2. How many different part models will I be testing that have the same clinical usage?
3. Will this be a single production line or multiple lines?
4. Will the testing station be manual loaded/unloaded or automated?
5. Will an instrument with a benchtop or wall-mount form factor be more suitable relative to the device position/fixturing?
6. What are my throughput needs (short- and long-term)?
TEST INSTRUMENT SELECTION
7. Will my leak and blockage tests be based on pressure/vacuum loss only?
8. Will I need to grade the amount of blockage using mass flow?
9. Can my test pressure remain static, or do I have the need to ramp pressure/vacuum during the test?
10. Will I need to verify the device’s pressure/suction at some point during test?
11. Do I need to verify a certain part volume is present in the zone I’m testing?
12. Will the tests I’m doing remain fixed forever or do I potentially need future flexibility to change pressure or flow measurement ranges or add test types?
13. What level of precision/accuracy is needed?
14. Do I have any test repeatability targets (Gage R %)?
15. Will I be testing single or multiple parts presented to the test station at a time?
16. If multiple parts, can they be tested sequentially or will I need to test them concurrently?
17. If concurrently, is it better to test them all synchronously (together) or asynchronously (as soon as each is ready)?
18. Do I need to communicate test results/variable data back to a PC/Network/SPC software?
19. Do I have 21 CFR Part 11 requirements?
MATING THE PART TO INSTRUMENT
20. Will my operators easily be able to connect each part to the instrument/fixture manually using fixed metal luer fittings or press-fit tubing connections?
21. Would I prefer instead to use pneumatically actuated seals which minimize fatigue and ensure consistent mating part contact from test to test?
22. Would my process benefit from error-proofing such as holding failed parts pneumatically sealed until a reset button is pressed to acknowledge the failure?
23. Would the process benefit from fixturing or even a turnkey test station instead of an instrument by itself?
24. If turnkey, do I have any fixture repeatability targets (Gage R %)?
Questions to ask suppliers
Once you’ve defined what you need out of an instrument, you also need to understand what you need out of a supplier. Without your desired level of support, a solution is not going to be the right one for your line. Below is a list of questions to ask any supplier to help find the right partner:
1. Does the supplier have a lab to prove my requirements are feasible before I buy, and if so, are there added costs for doing this?
2. Does the supplier’s instrument meet my precision/accuracy requirements and can certify this on the calibration documents?
3. Can the supplier offer ISO-17025 accredited certification for pressure and flow calibration both at the factory and in the field if needed?
4. Does the suppler offer only the testing instrument(s) or can they also offer the mating connections, accessories required?
5. If I start buying an instrument only, can this supplier later integrate this into a more advanced turnkey solution later if needed?
6. Does it appear that this supplier’s production portfolio not only cover today’s needs but for other unique projects I may need to test in the future?
7. Do I need the supplier to provide local support to only location only, or multiple locations, possible globally?
8. What are the suppliers hours of technical support availability vs my actual production schedule?
9. If I need a field service technician, does the supplier have a team available or are they limited access production team members who often are not permitted to leave the facility?
10. How long is the supplier’s warranty on what I intend to purchase?
11. Does the supplier charge for non-warranty phone support?
12. During the next economic downturn, does the suppler have the financial backing/fortitude to remain in business?
Consult the Medical Device Leak Testing Experts at CTS
CTS provides the industry’s most precise assembly failure detection solutions for medical device manufacturing. We have a testing lab and service center, complete test laboratory, no charge feasibility testing, and test optimization testing available. Contact the leak test experts at CTS to answer any questions you may have and help you in the development of your testing process for disposable medical devices.
Last Post