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Operational Qualification: Step Two in Ensuring Reliable, Predictable Operation of Your SPD Equipment

“When all else fails, read the manual.”—Jonathan A. Wilder

In one of my previous articles for NewSplash, “The Nuts and Bolts of a Quality System,” I wrote about the three aspects of equipment qualification: Installation Qualification (IQ), Operational Qualification (OQ), and Performance Qualification (PQ). This article is a deeper dive into the second of these, Operational Qualification. OQ is the step in qualification of the equipment in which we get to answer the question, “Does it do what I expect it to do?” OQ provides a baseline so that you know what the machine is capable of right after handoff from the installer or manufacturer, so you can know if things aren’t going as well as they could (should!) later in its lifetime.

In that article, I provided a comparison between what the AAMI/ISO 11139 definition of OQ is and my interpretation of it. Once again…

It passes IQ
The testing done during commissioning either by you or by the installer or manufacturer was successful. You are providing the machine with what it needs to run, and the machine provided to you is what you requested.

It does what it is supposed to do
This includes what is listed in the table above as “It runs cycles correctly and in specification.” If it has power doors, they open and close when you tell them to. If it has an automated loader, it only loads when the door is open and a load is present to load. And so on. The cycles run with phases in the right order. The performance of the cycles meets the requirements of the applicable standard or manufacturer’s specification.

If the cycles do not meet specification, it informs you of the situation
If the temperature is too low, it signals an error. If there is a utility issue (water, steam, air), it signals an error. If the door is jammed, it signals an error. You get the idea.

Basic template for an OQ protocol and report

  1. Has IQ been successfully passed?
    1. If the answer is not Yes, do not pass Go. Return to the IQ and make sure everything is as it should be. If you don’t, you are starting from a compromised position and may void your warranty.
  2. Do automated parts of the machine do what they are supposed to do?
    1. Test the power door(s), if any.
    2. Test the autoloader/unloader, if any.
  3. Cycle testing (to be done with empty chamber)
    1. Start with the simplest cycle. For a steam sterilizer, this will be a leak test.
    2. Proceed to the next simplest cycle. For a steam sterilizer, this will probably be a gravity cycle.
    3. Continue through all cycle types that you will use.
    4. For washers, you also have to check that detergents and lube (if used) are being dosed and the dose is the programmed amount.
    5. Testing should always be done with a rack, cart, or trolley that is at room temperature in the chamber.
    6. Test all racks that you plan to use in a washer and try to see that the spray arms rotate or, for lumen racks, that all irrigation channels have water or detergent solution coming out of them while the cycle phases are active.
    7. You can also do empty chamber testing of indicators (cleaning indicators for washers, sterilization indicators for sterilizers). If you don’t pass in an empty chamber, you will never pass Performance Qualification.
    8. If you have access to temperature dataloggers, you should use these to get an independent read of the temperatures during the cycles to make sure that the specifications are met (–0/+3°C for steam sterilizers during exposure, –0/+5°C for washer-disinfectors, for each phase with temperature control).
  4. Error case testing
    1. Block the door, tell it to close, and see if the controls figure it out by responding with an error code. Check with the manufacturer to make sure you aren’t going to break the door mechanism.
    2. Try to start a cycle with the door open.
    3. Check interlock behavior. For example, if a machine has a load and unload door, they should never be allowed to be open at the same time, except for service mode.
    4. Check the autoloader by trying to use it without a load on it.
    5. Start a cycle and close a shut-off valve for a critical utility.
    6. Start a cycle and shut off the three-phase power (if the unit has controls that are power independent of the three-phase power).

When doing this for industrial-level OQ, I simulate errors that test all error cases of the control system, such as overpressurizing the chamber. (I remove the pressure transducer and connect it to a modified bicycle pump. I do not want to carry shrapnel from a failed chamber for the rest of my life!) I also disconnect transducers to simulate transducer errors, and other things that are not for the untrained or faint of heart. These are parts of an OQ that would be done for a medical device or pharmaceutical facility. In your case, since the manufacturers of your devices are regulated by the FDA, even for non-510(k)-cleared devices like washer-disinfectors, you can be sure that the manufacturer has validated the response of the controls to more-extreme cases like these.

Similar testing of, for example, vaporized hydrogen peroxide sterilizers, ultrasound probe disinfectors, ultrasonic washers, etc. can also be done, and should be.

As I said last time, this is a lot of work. But it tells you that the machine is in good working order when it is new and, more importantly, what you can expect of it. In industry, machines are requalified annually after maintenance to make sure that performance is what it should be and, more importantly, what it used to be when it was new. If things go downhill, you will have documented proof that they have, which is a real asset for warranty issues.

Okay, it’s done and documented. The next and final step, PQ, will be described in the next article in this series.


Dr. Jonathan Wilder has worked with all thermal and chemical sterilization methods, as well as cleaning and disinfection methodologies, bringing his background in physical chemistry and surface physics to bear upon difficult problems in the field. He has been an active participant in U.S. and international standards development since 1998 through AAMI. As of January 2018, he is the cochair of the U.S. standards-making committee for hospital steam sterilizers.

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