FREE 5L Cubitainer Clear Gel

When you purchase a case of SONO Ultrasound Wipes

Shop Now

High-Level Disinfection Definition

What is high-level disinfection?

High-level disinfection is a process that is used to treat medical and dental devices and instruments to completely kill viable microorganisms, except for a small number of bacterial spores and prions.

This should be followed by a cleaning process that should inhibit enough pathogens to prevent infection from being transmitted.

This process of disinfection also refers to the reprocessing of semi-critical dental instruments and medical devices that cannot be sterilized by traditional methods or are heat-sensitive.

For a better understanding of this definition, semi-critical devices refer to devices that come in contact with non-intact skin or intact mucous membranes and are not designed to penetrate tissues or other sterile areas of the human body.

High-level disinfection is regarded as the common alternative in sterilizing both critical and semi-critical medical devices that are heat tolerant and meant to be used more than once.

High-Level Disinfection Methods

The Association of perioperative Registered Nurses (AORN) published new guidelines, among which are the high-level disinfection guidelines. High-level disinfecting should be done using these steps:

  • Reusable semi-critical devices or instruments may be disinfected using manual methods, as recommended by the manufacturer.
  • The organization’s interdisciplinary team should decide on what high-level disinfectants (HLDs) to use and where to store them.
  • The disinfection process should be done in areas controlled and maintained with the intention of processing items in it.
  • Items for processing should be prepared according to the manufacturers’ instruction for use (IFU).
  • Reusable semi-critical items that have been disinfected using HLDs must be protected from contamination until they are once again set to be used.
  • The organization must keep a record of the disinfection processes.
  • The personnel who handles and stores HLDs must be kept safe and protected.
  • The personnel handling HLDs must be provided ongoing education and competency activities regarding the use of the disinfecting chemicals.
  • The organization should develop and implement procedures and policies for the high-level disinfection process and review and revise them regularly.
  • The processes must be subject to regular evaluation to maintain their quality and effectivity.

Are Medical Probes being Adequately Disinfected?

A number of alarming studies show that 3-7% of transvaginal ultrasound probes remain contaminated with human papilloma virus (HPV) DNA after the routine disinfection of ultrasound and medical probes and equipment.

These and other reports suggest that inactivation of all microbial pathogens or high-level disinfection may not always be properly achieved, which mostly depends on the quality of used disinfectants. 

The requirements is that semi-critical devices are high-level disinfected, which includes the inactivation all microbial pathogens except large numbers of bacterial endospores.

The Reality

It is important to note that the HPV disinfection researches were conducted in France, and that the routine disinfection practice in France is often only a Low Level Disinfection, typically performed with quaternary ammonium compound wipes.

Low level disinfection would not be expected to be effective against non-enveloped viruses such as HPV as they have a higher level of resistance to disinfection.

NOTE: The U.S. guidelines and standards recommend High-Level Disinfection of ultrasound probes, while this can vary internationally.

High-Level Disinfection and HPV

A recent study found that certain types of high-level disinfectants, based on glutaraldehyde and OPA, were ineffective against the HPV virus even after prolonged exposure.

The study concluded that oxidation-based disinfectants may be more effective at inactivating HPV. A 2015 study by Meyers confirms that hydrogen peroxide was effective in achieving a >4 log10 reduction of HPV16 and 186.

Similar results have been published for other, highly resistant non-enveloped viruses such as parvoviruses and bacteria such as aldehyderesistant bacteria.

Non-Enveloped Viruses

HPV16 and 18 are classified as non-enveloped viruses. To demonstrate effectiveness against these and other viruses, the FDA requires the use of poliovirus as the marker virus.

The resistance profiles of other non-enveloped viruses (human and animal pathogens) have been investigated. These include parvoviruses, coxsackieviruses, other enteroviruses, hepatitis A virus and noroviruses.

Disinfection studies have shown that some of these viruses are distinctly more resistant than the poliovirus marker, in particular in studies with aldehyde-based disinfectants.

The most resistant to date are the parvoviruses. Parvoviruses are small (18-26 mm), non-enveloped, hydrophilic, single-stranded DNA viruses.

High-Level Disinfection of Ultrasound Probes

High-level disinfection for ultrasound probes is necessary for the sake of the patients, your healthcare team, and your reputation, which will certainly affect your bottom line.

This is because transrectal, transvaginal and transesophageal probes are considered as semi-critical items that require high-level disinfected when used between patients.

Ultrasound probes are used in the vascular system or sterile body cavities, hence the need for sterilization.

But since they are heat sensitive, they also need to be reprocessed by soaking them in high-level disinfection products.

On the other hand, general surface probes that are used on the breasts or abdomen are considered low risk, so they only need low-level disinfection, not necessarily high-level disinfection wipes.

But it’s a different story altogether if they are used in cases where biopsy is performed. The risk rises and general surface probes will need high-level disinfection solutions.

This level of disinfection is necessary for the probes’ built-in channels for the needle guide, for the needle guides that penetrate sterile tissue, and for the probes that are used on a non-intact skin or on high-risk patients.

To properly perform high-level disinfection of ultrasound probes, you also need to choose the right disinfectants.

You need to consider the time it would take to disinfect the probes, cost per cycle, reuse period, ventilation requirements, transducer compatibility, contraindications, and rinsing requirements.

When you start using chemicals such as the Resert high-level disinfection solution, make sure to follow the FDA-cleared exposure time or the time recommended by the manufacturer.

Don’t buy disinfectants with quaternary ammonium compounds because these are mostly used in low level disinfectants. While probe covers are recommended as part of your safety measure, they are not enough to prevent contamination, hence the need for high-level disinfection.

High-Level Disinfection Checklist

  • Devices are visually inspected, cleaned again as needed before starting the high-level disinfection process, and maintained according to manufacturer’s instructions.
  • Disinfectants are prepared, tested for the minimum effective concentration (MEC) according to guidelines, manufacturer’s IFU, and infection control policy, and discarded if concentration is lower than MEC.
  • Disinfectants are documented, whether prepared or replaced.
  • Semi-critical devices are high-level disinfected following manufacturer’s IFU, hospital policy, and evidence-based guidelines.
  • Items that have been disinfected are dried properly before reuse.
  • Items are properly maintained.
  • The test strip bottle is marked with proper dates and not used beyond expiry.
  • Personnel who handle HLD have attended training or class and should know how to interpret color differences in test strips for MEC.
  • Flexible endoscopes should be checked for leaks before high-level
  • The disinfectant for HLD is perfused into the channel using a syringe to ensure that that they kill microorganisms.
  • Endoscopes are rinsed and channels are flushed with rinse water or tap water followed by a 70-90% alcohol.
  • Endoscopes or semi-critical items are hanged or stored in areas that prevent recontamination.
  • Water bottle and its connecting tube used for intraprocedural flushing should be sterilized or high-level disinfected at least once every day and filled with sterile water. An alternative would be to use sterile disposable bottles.
  • Disinfection must be done in a safe environment for the personnel.
  • Personnel must wear a gown, gloves, eyewear, face shield, and others to protect them from exposure to chemicals.
  • High-level disinfectants must be used at the FDA-cleared exposure time.
  • Healthcare organizations should have a strategy that prevents their patients’ exposure to contaminated medical devices and instruments.

High Level Disinfection Policy

There are several challenges that are associated with high-level disinfection, starting with its numerous steps and varying requirements for each medical instrument up to its high-risk if it is not performed properly.

It is usually not well-standardized across healthcare organizations, even in the same facility that uses the same equipment. This is why it would be best to develop a policy for high-level disinfection in hospitals.

By adopting a hospital-wide policy, it means that you have to post the manufacturer guidelines for the medical equipment and disinfectant required by each and distribute it to the entire facility. This should help simplify the process and improve compliance with high-level disinfection requirements.

Best to Use For

When it comes to disinfection of medical probes and equipment, regular disinfectants can not guarantee reliable result. That is when the risk of transmission of different viruses, fungus and bacteria is rising.

Presented high-quality medical high-level disinfectants are the best to use for sterilization of following medical probes and equipment:

  • Endoscope disinfecting cleaning
  • Laryngoscopes disinfecting cleaning
  • Arthroscope disinfecting cleaning 
  • Enteroscope disinfecting cleaning 
  • Bronchoscope disinfecting cleaning 
  • Laparoscope  disinfecting cleaning 
  • TEE disinfecting cleaning
  • Transesophageal  disinfecting cleaning  
  • Vaginal probe  disinfecting cleaning
  • Rectal probe  disinfecting cleaning
  • Vaginal transducer  disinfecting cleaning
  • Rectal transducer  disinfecting cleaning