Sterilization is a process which kills or removes any life forms which may be on the surface of an item. It is different from cleaning or disinfecting, which only remove major particles and life forms from surfaces. Sterilization is critical in medical applications to help ensure patient and medical personnel safety.
A Chemical Indicator (CI) is a physical or chemical device used to indicate exposure to one or more process parameters of the sterilization cycle. The CI will visibly change color from an initial starting point to a "distinctly different color" (ISO 11140-1:2014). Tempilinks serve as a critical component in the production of Chemical Indicators and are designed to change color indicating that the device being sterilized was exposed to the proper sterilization conditions for the process to which it was exposed.
Note: Tempilinks are not intended to replace biological monitors that directly measure spore kill, bacteria kill or elimination of other pathogens
Sterilization conditions vary significantly; however, Tempil inks have been designed with the following conditions in mind:
- Steam/Autoclave: Saturated steam at 250 F/121 C for 10 minutes (long cycle) OR Saturated steam at 273 F/134 C for 2 minutes
- EtO EO gas 600mg/l conc. at 130 F/54 C for 20 minutes, OR 99 F/37C for 25 minutes.
- Plasma: 6 min., 122 F/50 C, 2.3+/-0.4mg gas concentration
- Irradiation: E-beam & Gamma radiation 10kGy (1.0 megarad)
- Dry Heat: Dry heat at 320 F/160 C for 40 minutes
- Formaldehyde: Formaldehyde gas 1.0 mol/l concentration at 158 F/70 C for 15 minutes
Basic info to expedite the selection includes:
- Type of sterilization process
- Color preference (both print and signal colors)
- Solvent-based or water-based preference
- Printing technology
Tempilinks contain chemical components that must be present in a sufficient quantity and balance for the chemical indicator to signal properly. When viscosity adjustments are necessary, please refer to Technical Data Sheets for an appropriate solvent and guidelines for addition.
The ink signal color change can be impacted by several things. In all these situations, the ink will print well and look good in its initial, unsignaled color. Among the most common reasons for insufficient color change are:
- Not enough ink laydown. For most chemical indicator inks, too fine of an ink laydown will not deposit enough of the materials required to make the color change
- Inadequate mixing of the ink prior to printing. Tempilinks have high solids content to enable the signal color change. Failure to thoroughly mix the ink will not disperse the solids evenly throughout the ink, resulting in inconsistent signals. To learn more about how to use these inks, please refer to the Technical Data Sheet for the ink(s) you are using for mixing instructions.
- It is very important to check compatibility of the material being printed with the ink to assure sufficient ink laydown and adhesion is achieved. Although not common, sometimes the material being printed can cause a reaction with the ink, which prevents the signal color. Although this is not common, it is always important to check compatibility prior to printing.
- The sterilization unit may not be functioning properly. Although it is more common to think of the ink first, the intention of the ink is to confirm that the sterilization process has taken place. If the indicator is not changing color and it is not one of the other potential causes, make sure the sterilization system is functioning properly.
Warranties of inks vary based on the ink. There is not a common shelf live for all Tempilinks. Please refer to the Technical Data Sheet (TDS) for warranty shelf life information on the specific ink you are questioning.
Tempilinks will require different coating weights for development of the appropriate signal based on the substrate, the sterilization process, and the ink itself.
Tempilinks come in various colors; however, due to their indicating nature, inks cannot be matched to pantone color charts. Please refer to the Tempilink color chart for a directional overview.
Yes. It is important to consider the substrate when making an ink selection.
Coating weight, sterilization conditions, printing substrate, position in the sterilizer, and more.
Please note: Inks themselves cannot be compliant to ISO 11140-1:2014. The standard is specific to Chemical Indicators not the inks or coatings used to create them. Tempilinks have been printed on specific substrates to create ISO 11140-1:2014 Type 1 Chemical Indicators. Chemical Indicators' compliance with standards is dependent upon the specific conditions of your printing process (substrate, equipment, printer's skills, etc.).
Types of Medical Sterilization Indicators (Per ISO 11140-1:2014)
<td">"Type 2 indicators are intended for use in specific test procedures as defined in relevant sterilizer/sterilization standards."
|ISO 11140-1:2014 Definition||Applications|
|Type 1 (Formerly Class)||
"Printing of peel-pouch packaging for reusable and single-use devices, decontamination bags, and lid stock are common applications. Labels, tags, pressure-sensitive tapes, and dots can also be printed for use during on-site sterilization processes."
Pouches, reels, labels, and tape are all common examples of Type 1 Chemical Indications.
The Bowie-Dick Test packs are the most common application of Type 2 Chemical indicators. They are used to test the effectiveness of air removal for steam penetration of steam sterilization units.
"A single variable indicator shall be designed to react to one of the critical variables and is intended to indicate exposure to a sterilization process at a stated value (SV) of the chosen variable."
A chemical indicator which reacts to a single variable, such as heat only, is an example of Type 3.
"A multi-variable indicator shall be designed to react to two or more of the critical variables and is intended to indicate exposure to a sterilization cycle at SVs of the chosen variable."
Most commonly printed strips or labels, Type 4 indicators react to 2 or more variables, such as heat and steam, at established levels.
"Integrating indicators shall be designed to react to all critical variables. The SVs are generated to be equivalent to or exceed the performance requirements given in the ISO 11138 series for BIs."
May be used as an internal chemical indicator for pack control monitoring. Internal chemical indicators should be used inside each pack. • Can also be used as an additional monitoring tool to release loads that do not contain implants. For this application the Type 5 Integrating Indicator must be used in the appropriate Process Challenge Device (PCD).(2) • Should be used in a PCD to monitor implant loads. The PCD should also contain a BI. The implant should not be released until the BI result is known, except in emergencies.(2)
"Emulating indicators are cycle verification indicators which shall be designed to react to all critical variables for specified sterilization cycles. The SVs are generated from the critical variables of the specified sterilization process."
Type 6 indicators have limited use to date and are not currently controlled by ISO.