Type 4, 5 and 6 indicators are used inside each pack to be sterilized. If the colour of the indicator has fully changed, the penetration into the inside of the sterilized packs has been successfully. Provided that solely solid instruments – no hollow goods – are inside the package monitoring indicator can be used for routine monitoring. If only cross contamination on surfaces of the instruments should be prevented, the instruments are sterilized unpackaged. In special combination autoclaves that clean, lubricate and sterilize dental instruments, the indicator is also placed unpacked into the holder inside the chamber.

These indicators are available for steam sterilization processes to prove a successful steam penetration inside the package. They are also obtainable to monitor formaldehyde, ethylene oxide and hydrogen peroxide sterilization processes.

If hollow instruments, e.g. trocars, have to be sterilized it has to be proven that the sterilization agent penetrated not only inside of the package but also inside of the hollow device. This is not possible with a package monitoring indicator, as it is not placed inside of the hollow instrument. In this case a process challenge device test system has to be used and its testing characteristics must be qualified for the load to be sterilized. Depending on the load a process monitoring system or batch monitoring system which is related to the load can be used.