Topics 1 – Types of Chemical Indicators (Type 1)
The six main types of Chemical Indicators used in sterilization processes at medical institutes are listed below.
The roles and properties of each type differ as detailed below.
Let’s begin with Type 1.
Although simple, Type 1 is an extremely important Chemical Indicator.
Let’s consider the following question. Here we have two items for sterilization. Which one has been sterilized?
Anyone who knows the answer right away would have to be a real expert on sterilization!
That’s right. No matter how long you look at the two items, you’ll never be able to determine which has been sterilized and which hasn’t. Being able to tell the difference in a real-life situation is critical. What we need is something that will make it possible to distinguish between the two at a glance.
This is where the Type 1 indicator comes into play!
On our sterilization pouches, the Type 1 indicator you can see above changes from white to reddish brown when AC sterilization (Steam sterilization) has been completed. Incidentally, when the above sterilization pouch is sterilized by EOG (ethylene oxide gas), the pink indicator on the right changes to blue, so the pouch can be used for both AC and EOG sterilization.
Also known by the name “Process Control Indicator,” this Type 1 indicator is used for process control, as the name indicates.
Taking out an instrument that has not been sterilized by mistake can expose patients to serious risks posed by unsterilized equipment.
To prevent such situations, Type 1 is an “extremely” important indicator.
This Type 1 indicator is used in various ways. As well as the sterilization pouches shown above, Type 1 indicators are also used in products such as sterilization tapes and labels.
These are all affixed to the exterior of packages. Why do you think that is?
That’s right! Type 1 tells you whether or not an item has been sterilized at a glance!
Tapes or labels are affixed to the outside of packages so you can tell right away whether or the contents have been sterilized.
That’s why the Type 1 indicator is also categorized as an “Indicator for package exterior” (The number of different names for this type is confusing, isn’t it? We‘ll list the different names in later issues of this column.)
The above is a brief description of the Type 1 process control indicator, a type that appears simple, but in fact, plays an extremely important role in sterilization.
That concludes this issue. In the next issue, we’ll be looking at indicators on the contents of packaging (Types 3 – 6). 
Please contact us anytime if you have questions.