May 28, 2024


Education is everything you need

The Number One Reason Your Tuttnauer Autoclave Tests Positive For Biological Indicators

The CDC recommends that you test your autoclave for biological indicators at least once a week and this is one of those times when you want a negative result. A positive result means that live spores were found on your test sample and that means there’s a problem with your autoclave. Thankfully, aside from human error, there’s one leading cause for your Tuttnauer autoclave to fail the spore test – a faulty or clogged air jet valve.

An early indicator that you might be having problems with your autoclave is if the indicator strip on your sterilization pouch doesn’t change colors. Remember, first, if the strip does change colors that only means that your autoclave was reaching the proper temperature, not that your instruments were being properly sterilized. However, if the strip fails to change colors during the cycle, then you definitely have a problem with your autoclave.

When you get that negative test result, the first thing you should do is make sure your staff did everything they were supposed to do. Did they set the time properly? Did they make sure the water reservoir was full? Did they let it run through the complete cycle before they opened the door? And were all your instruments packaged and loaded properly?

If you can rule out operator error then your very next stop should be the air jet valve and it’s located inside the reservoir. The air jet valve allows the cool air inside the chamber to escape while the chamber is heating up. The hot steam forces the cool air out through this valve and if that cool air can’t escape then there will be air pockets inside the chamber. These pockets of cool air prevent the pressurized steam from fully sterilizing your instruments, which is why you failed the spore test.

This valve is also open all during the cycle to allow small amounts of steam to escape, which is why you sometimes hear a slight hissing noise during operation. This purging keeps the steam in motion and helps maintain a constant temperature inside the chamber. Without this constant motion cooler pockets of steam would develop and again, there’s another reason you might fail the spore test.

These cooler pockets of air can have several different effects. You might think there’s a problem with the heating element or a problem with the temperature sensor or even a problem with the pressure gauge. But if you check the air jet valve first you’ll probably be able to solve your problem right there.

How hard is it to clean the air jet valve? Well, do you have a minute? Because that’s all it’s going to take!

First, remove the cover from the water reservoir and locate the valve. Using a pencil or a screwdriver or something similar, place it through the loop at the end of the valve. This loop is actually at the end of the clean out wire. Now all you have to do is pull the wire in and out ten times to clean out the valve. This works best if you do it while your Tuttnauer autoclave is running so the pressure will blow out any debris that’s clogging the valve.

Put the cover back on the reservoir and your problem is solved. Just be sure you clean that valve every week, or more frequently if needed and you shouldn’t have anymore trouble.