The ever-present threat of healthcare associated infections (HCAI) has made sterility assurance a key consideration for healthcare providers worldwide.
Effective sterilization of hospital equipment between patients is a vital aspect of infection control, but how do you know that the processes you have in place are working effectively and efficiently? Sterilization processes have critical parameters which must be attained if the process is to be successful. For steam sterilization, the key parameters are time, steam and temperature, however it is not always possible to measure these parameters at all points during a cycle.
A properly calibrated and validated chemical indicator will easily show non-attainment of certain physical parameters, but how can you be certain that your sterility assurance measures are functioning correctly? Chemical indicator systems can provide rapid visual verification that sterilizer cycles are performing correctly and delivering the necessary physical parameters within the load. These technologies work by being extremely sensitive to both temperature and humidity, and can detect temperature differences as small as 1 oC.
Basic ink technologies, as used in autoclave tape, were conceived in the 1930s and are usually lead-based, exhibiting a gradual white to black colour change. Other heavy metals offering similar properties to lead-based inks, such as copper, have also been used as active ingredients of chemical indicator systems, and technologies based on hexavalent chromium also exist. These chemical indicator systems all rely on a gradual colour change of the active components themselves (Figure 1), and this system of progressive darkening can make the final indicator endpoint (pass/fail) difficult to determine.
To overcome this ambiguity, Albert Browne has developed Intelligent Ink Technology, an advanced sterilization indicator chemistry offering clear, well-defined and abrupt endpoint colour changes to allow clear and straightforward ‘pass/fail’ decisions. This gives you complete confidence that sterilization conditions have either been verified or have failed. Intelligent Ink Technology relies on unique, lead-free ink formulations to provide an easy to interpret colour contrast. The colour change has been carefully selected to reduce the risk of incorrect interpretation of the indicator; it is both tonal – it can be seen in black and white – and uses colours selected from different ends of the colour spectrum. Its second order reaction chemistry means little colour change is observed before the endpoint is reached towards the end of the sterilization process (Figure 2). Today, this technology forms the basis of both the TST Bowie Dick Test Pack and TST Control™ products, providing straightforward, unambiguous and fully ISO 11140 compliant sterility assurance.
