Sterilization Classes | Painful Pleasures Community

Sterilization Classes

It's important to regularly check your autoclave to make sure that it's working properly--a task you can accomplish using a variety of chemical indicator (CI) tests. There are 6 different classes of CIs, 5 of which check to ensure that different components of an autoclave's core processes are working and 1 that includes an additional biological testing component. We break down the 6 classes and explain why tests from some classes are better than others.

by Danny Tress Last Updated: April 18, 2024

If you own a tattoo and piercing shop, hopefully you also own an autoclave. As we’ve discussed at length throughout our Sterilization Series, sterilization by steam via an autoclave is the superior method to use to sterilize tattoo and piercing tools and body jewelry. Ideally, you should bag tools and jewelry in sterilization pouches before autoclaving them. Doing so gives you the best opportunity to test the effectiveness of the sterilization process in addition to keeping all bagged items sterile until the time they’re used. How does bagging items before sterilizing them help ensure that the sterilization process is successful? Through the use of chemical indicators (CIs).

Chemical Indicators

Chemical indicators are tests that prove your autoclave is working as it should be. Different tests show different things, ranging from a simple confirmation that an item was run through a steam sterilizer to a complex combination of biological and process checks that confirm that (a) the 3 elements required for an autoclave to function properly are all working harmoniously, and (b) no spores are present at the end of the test. These varied tests each fall into one of 6 sterilization classes.

The 6 Sterilization Classes

Sterilization Class 1: Basic Process Indicators

Basic sterilization process indicators confirm whether or not a steam sterilization process occurred at all. These are yes/no tests. They come built into many sterilization pouches, they can be applied to sterilization pouches using autoclave indicator tape, or you can purchase internal steam indicators that go inside your sterilization pouches or nylon sterilization tubing. The benefit to internal steam indicators is that you can’t cheat the system when you use them; a packet has to actually go through a full autoclave cycle for an internal indicator to change colors and confirm that the packet was autoclaved. That’s in contrast to the process indicators built into sterilization pouches, which you could technically make look like they’d been autoclaved just by holding them over a steaming pot of water. That’s not something any legitimate tattoo or piercing artist would ever do, but since it is possible, you can give your clients added assurance that you care about their health and don’t cut corners by using internal steam indicators, too.

Sterilization Class 2: Specific Test Indicators

Specific test indicators do exactly what they sound like they do: they test for very specific things. For instance, you can check an autoclave for air leaks or confirm that air is being properly removed from the sterilizer using a Bowie-Dick Test.

Sterilization Class 3: Single Variable Indicators

There are 3 key elements that must run in sync for an autoclave to function properly: steam, temperature and time. A single variable indicator checks to ensure that one of those three elements is working. For instance, you may perform a temperature test that yields a specific result once the autoclave reaches the temperature necessary to sterilize the packaged contents. It could be as simple as looking to see if a contained object was melted once the autoclave cycle is complete.

Sterilization Class 4: Multi-Variable Indicators

Multi-variable indicators confirm that two or more elements that are critical to the sterilization process functioned properly while the autoclave was running. They may test steam presence and temperature, time and temperature, or a combination of all three critical elements.

Sterilization Class 5: Integrating Indicators

Class 5 tests are called integrating indicators because they integrate biological indicators with process indicators. Biological indicators (BIs) confirm that no spores remain at the end of an autoclave cycle, while all three critical elements of the sterilization process–steam, temperature and time–are also confirmed.

Thanks to the triple process check plus the addition of a biological check, class 5 CIs are typically the most thorough test you can run to confirm that an autoclave is working as it should and fully sterilizing the items being run through it. Medline Class 5 Steam Integrator Strips are a perfect example of class 5 CIs.

Medline Steam Indicators

Some shops use a Medline integrator with each batch of tools and/or jewelry they autoclave, others use them periodically, while others yet choose a test from one of the other classes to use with each batch and then run an autoclave spore test separately at least once a month. The latter option isn’t a single test that can be considered a class 5 indicator, but it provides similar information about the way your autoclave is functioning and is a more affordable option.

Sterilization Class 6: Emulating Indicators

Emulating indicators respond to three variables for a specified cycle, meaning a unique combination of temperature, time and steam used to sterilize glassware vs. metal tools within sterilization pouches and other items that require different settings to be fully sterilized. For this reason, they’re sometimes called cycle-specific indicators. There’s no biological indicator component to a class 6 test, so in that respect, it’s inferior to a class 5 test.

Monitoring Your Autoclave

Tuttnauer autoclave machine

Whichever of the autoclave testing methods above you choose to employ in your shop, the important thing is that you regularly check your autoclave to ensure that it’s functioning properly, killing microorganisms effectively, and protecting your clients’ health. Visit our Medical Supplies section to find all the tools you need to achieve that goal, including autoclaves, sterilization pouches, nylon sterilization tubing, a variety of autoclave indicators, and more.

More Information About Sterilization

This article is part of a 6-part series on sterilization methods, typical tattoo and piercing sterilization techniques, and alternatives for smaller tattoo and piercing shops. To read more about a specific aspect of sterilization, click the related article below.

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