A Time for Disinfection

We do it several times a day, every day we work in the laboratory. We disinfect, but how much do we really think about what we are doing? Some may think we disinfect our benches at the end of the shift because it is expected, and that we only perform this task because it is listed on our maintenance log. Others disinfect at the beginning and at the end of their shift because of how they were trained. Since the pandemic, I bet many lab techs, nurses, and hospital staff disinfect religiously out of fear of catching COVID. The real reason we disinfect is to keep ourselves, our coworkers, and the people we care about safe.

As laboratorians, we have practices to preemptively and proactively ensure that the samples and patients we work with do not put us in harm’s way. We clean and disinfect anytime we have a spill of patient specimen. With that spill we know there is a potential for exposure, and we take steps to remove the threat. We also routinely disinfect our work areas throughout the day to eradicate any unseen pathogens. It is easy to visually spot a spill of whole blood, but a few drops of serum or plasma can easily go undetected.

To keep everyone safe, we need to fully comprehend the difference between “cleaning” and “disinfection.” Cleaning is the act of removing the physical component of a spill, sample, or mess. This could be dirt, dust, blood, body fluid, or even a piece of tissue. If there is a spill of blood on the floor, we first clean up the spill by applying an absorbent and sweeping up the material. We can see that the blood is removed from the floor, but what we cannot see poses the most danger. Simply cleaning up a spill does not kill any potential pathogens. We still have one more step, disinfection.

Disinfection is the process of killing the pathogens and it must take place after cleaning. Only after we disinfect is the area considered safe. It takes both the cleaning and disinfection steps to make sure the spill is properly handled. Spraying bleach directly on a blood spill and wiping with a paper towel may leave pathogens under the spill lurking on the surface of the floor or counter. For disinfection to be the most effective, it is essential to expose the potential pathogens to the disinfectant, and cleaning helps remove any barriers.

We have the why behind the process, so let’s discuss how we disinfect. Our best defense against most pathogens is bleach. Ah, the glorious smell of bleach; either you love it or hate it. Bleach is one of the few products that can effectively neutralize Clostridium difficile. That is why bleach is used for benchtop and post-spill disinfection. In the lab setting, we typically see two types of bleach products, a spray and wipes. Each has their own minimal contact time, so make sure to leave the product on the area for the allotted amount of time. Bleach wipes typically require a longer contact time than bleach spray. It is also important to make sure the lids on any disinfectant wipe container remain closed when not in use. If the lids are left open, the wipes can dry out, making them a less effective disinfectant.

Some labs may allow for a bleach alternative when employees with a bleach allergy are present in the lab. Individuals with a documented bleach allergy may be permitted to use alternatives such as a concentrated broad-spectrum quaternary agent as a means for disinfecting. Usually, approval must come from an organization’s employee health or physician to accommodate the request. As with bleach wipes, quaternary disinfectants may require a longer contact time than your usual bleach spray.

You may see products from other manufacturers that use alcohol with an ammonium chloride ingredient. Many labs use these types of disinfectants in areas to eliminate the residue seen when using a bleach product, such as cleaning stainless steel biological or chemical safety hoods, glass, or other office appliances. Often, alcohol or ammonium chloride disinfectants are used on telephone headsets, computer screens, select Point of Care instruments, and other items for which bleach is prohibited. In addition, some instrument manufacturers recommend only using a particular product to clean the surface of their equipment to ensure the cleaning does not damage the outer casing or internal components. Sometimes, though, staff will accidentally substitute these types of products in place of bleach when it is time to disinfect at the end of the shift or help with a spill. It may be convenient to just grab a bottle of an alcohol-based disinfectant and jump into action. However, it is more important not to take short cuts and locate a bottle of bleach spray and disinfect the proper way. Sometimes it may seem like a hassle, but disinfection is part of our laboratory culture, and we need to keep up with the practice. If we maintain our disinfection routines, there is no reason to doubt our safety inside and outside of the lab. You can take it a step further and always be on the lookout for expired products or open lids to ensure your products can do their jobs effectively. Understanding why we perform these tasks and the importance they have for our safety is something that should be shared with all employees. Together, with the right mindset, you can be confident that your lab is a safe, clean, and properly disinfected lab.

-Jason P. Nagy, PhD, MLS(ASCP)^CM is a Lab Safety Coordinator for Sentara Healthcare, a hospital system with laboratories throughout Virginia and North Carolina. He is an experienced Technical Specialist with a background in biotechnology, molecular biology, clinical labs, and most recently, a focus in laboratory safety.