Everything You Need to Know About High-Level Disinfection

Everything You Need to Know About High Level Disinfection

We need to prioritize our health and safety. You cannot be so sure in times like this where viruses and deadly pathogens are lurking. Cleaning is one way of making sure that you will not get in contact with the enemy – but really, what is high-level cleaning – the difference between cleaning and high-level disinfection?

Commercial cleaning companies in Australia have come up with different antiviral Sanitisation and Disinfection Cleaning Services. Various high-level disinfectants are used depending on the type of business that they service. Some also use germicides and hydrogen peroxide. A cleaning specialist needs to be knowledgeable about this. Join us today as we dive into learning what we need to know about high-level disinfecting and coronavirus cleaning.

Disinfection and Sterilization Process

Disinfection and sterilization are essential components of any infection control program.

Disinfection is a process that eliminates many or all microorganisms on surfaces and inanimate objects, except bacterial spores. Chemical and thermal high-level disinfection are such methods.

Sterilization describes the process that eliminates or fights all forms of microorganisms and is often used in healthcare settings by chemical or physical methods.

Steam under pressure, dry heat, ethylene oxide gas, hydrogen peroxide gas plasma, and liquid chemicals are the principal sterilization agents used in health care facilities.

Disinfection and sterilization are essential in ensuring that surgical and medical instruments or other materials do not transmit infectious pathogens to the patients. If we fail to disinfect or sterilize equipment properly, it will carry not only risks associated with the breach of host barriers but also risks from person-to-person transmission. It can also be the primary source of transmission of environmental pathogens.

Common Methods of High-Level Disinfection

Disinfection is completed with the use of chemicals. The chemicals are classified as:

  • High-level disinfection – characterized by being presidial and with prolonged contact, it can be used as a sterilant.
  • Intermediate-level disinfectant – This type of disinfectant cannot inactivate a large number of bacterial spores but are effective against e g mycobacterium tuberculosis, fungi, lipid and non-lipid virus, and hepatitis B virus. A few examples of these are, e.g. chlorine compounds, phenolics, and isopropyl alcohol
  • Low-level disinfection- this is unreliable against bacterial spores, mycobacterium, or small or non-lipid viruses. This can rapidly kill vegetative bacteria, most fungi, and medium-sized lipid-containing viruses. Non-critical items which do not come in contact in sterile areas, body tissue membranes, are acceptable after low-level disinfection, e.g. patient trolley, furniture, and bed rails.

Classification of Patient Care Items

The classification is based on the risk presented.

Non-Critical Items

These are the items that come in contact with intact skin, not with mucous membrane, e g bedpans, chairs, linen, blood pressure cuffs, walls, and floors. Non-critical items can be disinfected with low to intermediate disinfection. You may use ethyl alcohol.

Semi-Critical Items

Items that are exposed to mucous membrane and non-intact skin, e g are respiration tubing, bronchoscopes, endoscopes, and laryngoscope blades. A high-level disinfectant is necessary. You may use Glutaraldehyde.

Critical Items

Items that come in contact with tissue membranes or a vascular system, e.g. surgical instruments, and vascular catheters. Sterilization is necessary. Autoclaving usually is used in this setup.

Choosing the Appropriate Disinfectant

The critical parameters are:

Concentration – an optimum concentration of disinfectant ensures the highest efficacy, and it takes a short time to achieve microbial kill in all areas where this work is done.

The instruction must state the concentration that is needed, and it must give a detailed description of how the concentration is to be made. Do not mix disinfectants with detergents.

They can be incompatible with each other. Several physical and chemical factors also influence the high-level disinfection procedure.

It includes temperature, pH, relative humidity, water hardness, and containers.

A remarkable increase in temperature causes the high-level disinfectants to degrade, which weakens their germicidal activity. Not to say the least, it can also pose a potential health hazard.

If pH is increased, it will improve the antimicrobial activity of some disinfectants but, it decreases the antimicrobial activity of others.

The relative humidity is the second most important factor influencing the activity of gaseous high-level disinfectants or sterilants such as ethylene oxide and chlorine dioxide.

Water hardness is defined as a high concentration of divalent cation. It reduces the rate of killing of disinfectants because divalent cations like magnesium, ortho phthalaldehyde, and calcium in the hard water, interact with the disinfectants to form insoluble precipitates.

Containers must be clean and must not be topped with fresh, high-level disinfectants as fillable drops. The container must be covered with a tightly fitting lid to minimize the spread of toxic vapour.

Exposure – Items must be diluted to the disinfectant for the minimum contact time. The efficacy of disinfectants decreases if the contact time with the disinfectant is less than desired.

Microorganisms may be protected from high-level disinfectants by producing thick masses of cells, extracellular material or biofilms. Biofilms are microbial communities that are tightly attached to surfaces and cannot be removed easily.

Microbes within them can be resistant to disinfectant once the masses have formed. Bacteria within biofilms are up to 1,000 times more resistant to antimicrobials than the same bacteria in suspension.

Biofilms have been found in objects like whirlpools, dental unit waterlines, bed rails, and numerous medical equipment like contact lenses, pacemakers, hemodialysis systems, urinary catheters, central venous catheters, ultrasound probes, and endoscopes.

It can have severe implications for immuno-compromised patients and patients who have in-dwelling medical devices.

Organic matter interferes with the antimicrobial activity of disinfectants in the form of serum, blood, pus, fecal, or lubricant material. It can also interfere with the antimicrobial activity of disinfectants and also act as a physical barrier.

Disinfectants like iodine and chlorine disinfectants are prone to such interaction. Chemical properties should not be harmful to the item being disinfected—corrosion of metals or hardening of plastics as seen in cases of chlorine compounds.

Remove the corrosive disinfectant soon after application with a neutral combination like alcohol or detergent soap, and water. Disinfectants in use should be comfortable and safe to handle.

How to Increase the Effectiveness of the Disinfectants

Cleaning is the most crucial step in the high-level disinfection process. Organic matter, if present, will dilute the effect of active ingredients in the disinfectants.

If you cannot clean, you cannot sterilize or disinfect. Cleaning may be done mechanically using special equipment or manually.

One of the equipment used in mechanical cleaning is ultrasonic cleaners or washer-disinfectors. You should choose a liquid chemical that is compatible with this equipment and methods of cleaning.

Please read through to know the necessary steps for the workspace safe for coronavirus and the applied best practices in disinfecting.

Studies have shown that regular cleaning leaves residual proteins or biomaterial sticking to surfaces, especially in linens and hinges. Pathogens are trapped under these layers and do not get exposed to the disinfectants. It is a primary cause of infection.

All surfaces of the instrument and equipment must be cleaned, reaching all the channels and bores of the instrument if you decide to clean it manually. Dry the instrument using a drying cabinet or with a clean, lint-free cloth. Inspect to ensure that the instrument is clean.

Place the instruments in a high-level disinfectant like a multi enzymatic cleaning chemical. They are better than single enzyme cleaners as they contain multiple enzymes which digest protein, polysaccharides, mucopolysaccharides, and lipids. It is useful in removing traces of biomaterial sticking to the instrument and maybe even used in ultrasonic buds.

Ultrasonic cleaners or automated washers are recommended for cleaning the primary instrument that can withstand this process. Using the machine to wash the instruments will cut down on the handling of instruments. These cleaners must be compliant with CDC and national guidelines and standards.

Cleaners also need to follow the manufacturer’s guidelines. Ultrasonic cleaners are not appropriate for cannulated instruments as they cannot clean inside the instrument.

You cannot also clean instruments made out of plastic or metal material in an ultrasonic cleaner. It is not advisable for some glass instruments like syringes and lenses.

In general, after cleaning, it is vital to remove excess moisture from the items because it may dilute the disinfectant solutions.

When you see the term -side, it only means that the disinfectant has the killing action as its features. Germicide agents can kill microorganisms, particularly pathogenic organisms like germs. It includes both antiseptics and disinfectants.

Antiseptics are germicides that are applied to living tissue and skin. Disinfectants are antimicrobials applied only to inanimate objects and equipment.

Many disinfectants are used alone or in combinations like hydrogen peroxide and peracetic acid in healthcare facilities.

As best practices, cleaning specialists should read labels carefully to ensure that the correct product is selected for the intended use and applied efficiently.

Disinfectants are not interchangeable. Incorrect concentrations and the use of inappropriate disinfectants can result in hazards.

Precautions are important. Use of the appropriate personal protective equipment or PPE is imperative to protect yourself from occupational diseases. Proper ventilation is observed to minimize exposure.

Commonly Used Chemical Disinfectants in Healthcare Facilities


Alcohol (70 per cent), Isopropyl, Ethyl Alcohol – it can be used as bactericidal rather than bacteriostatic against vegetative forms of viruses.

They are Tuberculocidal, Fungicidal, and Virucidal. It does not destroy bacterial spores. The efficacy of alcohol drops sharply when diluted below 50 per cent of concentration.

For optimum results, the concentration should be between 60 per cent to 90 per cent water solution. It can be used on hard surfaces and tabletops.

Alcohols have been used effectively to disinfect oral and thermal thermometers and stethoscopes. It is flammable and toxic. Your staff who will be asked to clean needs to use this in a well-ventilated area.

Store the alcohol away from heat sources, hot surfaces and electrical equipment. After application, you need to let the alcohol dry completely.

Chlorine and Chlorine Compounds

Hypochlorites are the most widely used of all chlorine disinfectants. It is in liquid form, also called sodium hypochlorite. It can again come in a solid form that is called calcium hypochlorite.

In using sodium hypochlorite, you need to observe a 1 per cent dilution and a 4 per cent solution to be diluted. It can be used to disinfect materials contaminated with blood and body fluids or spillage.

You need to change the solution every 8 hours. You also need to observe a contact time of at least 20 to 30 minutes. Sodium hypochlorite has to be used under well-ventilated settings. Put on your PPE like gloves. It can be used for corrosive materials.

On the other hand, the bleach powder, also known as Chlorinated Lime, is used in the same application as sodium hypochlorite. It is more stable and contains more chlorine. It comes as a white powder.

You can prepare your cleaning solution by mixing 14 grams of powder in one litre of water. The average contact time is for 30 minutes. It is advisable to prepare the bleach solution every shift or 8 hours.

This disinfectant is corrosive to the metal in high concentrations. It can also discolour fabrics. When mixed with other chemicals, it can release toxic fumes. Chlorinated Lime works best in cleaning toilets and bathrooms.

High-level disinfection is best for patient care items in healthcare settings. There is a dedicated cleaning process for this to ensure adequate infection control and public health.

If you are aspiring to be a cleaner who will handle patient care, you need to make sure that you have undergone sufficient training from the environmental protection agency. You will need to have particular expertise to be successful in this field.

This is something that you will not learn overnight. Cleaning a healthcare facility is profitable, and we want you to follow us on our adventure. Join us in our success.

If you are a commercial cleaner in Sydney who can close a successful deal with a healthcare facility, I am excited to hear from you. Drop us a comment below and let the whole community know-how are able to land the contract. Share helpful tips and practices that will be beneficial to aspiring cleaners out there.

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About the Author

Hi, This is Amelia. I work as a commercial cleaning operations manager at Clean Group. I also handle the customer support responsibilities on behalf of the company through a team of 10+ fully trained support professionals. Besides managing a team of cleaners and ensuring healthy communication between clients and cleaners’ teams, I handle customers’ complaints and grievances, especially the ones that need special or immediate attention. If you need help sorting out the best cleaning for you or just want to chat, feel free to connect.

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