There are currently controversial discussions about the disinfection of ultrasonic probes, particularly with regard to the validation of wiping disinfection. The cleaning of the probes is practically not discussed and if it is, then it is only described or carried out as wiping cleaning. The evaluation of the sufficient removal of undesired contaminants to the extent required for further reprocessing is then made by means of protein detection. All of this really does not add up.
Vaginal and rectal probes are used with the use of a protective sleeve cover containing transmission gel. After the examination, the cover is removed and at best there may be smear contamination into the gel. Protein is rarely present and is not a suitable analyte to evaluate probe cleanliness. Probes are extremely contaminated with gel, which if not adequately removed can interfere with chemical disinfection, no matter how it is done. Therefore, an analyte must be used to evaluate the cleanliness, which makes the gels (carbomers) detectable as well and their removal assessable.
There are methods of fumigation with hydrogen peroxide or simply immersion disinfection that claim to be validatable in comparison to wiping disinfection. Only the problem of demonstrably sufficient cleaning has not been solved. All concepts of reprocessing or validation of reprocessing processes are based on the fact that cleaning is validated first and only when this is successful can disinfection be validated.
Since an evaluation of the cleaning, i.e. the sufficient removal of the transmission gel, has not yet been carried out for the reprocessing of ultrasonic probes, there can be no valid disinfection of the probes at present.
About the author
Dr. Winfried Michels has been a member of the AKI since 1985 and represented the manufacturers of washer-disinfectors for 30 years as head of application technology at Miele Professional. Since 2015, he has been running a test laboratory focusing on the topic of cleaning and has been an advisory member of the AKI since then.