How to Clean and Disinfect a Thermometer
From touch thermometers to pacifier-style ones, a doctor shares his expert opinion.
For as much as we depend on thermometers to keep us informed about our health, if we don't properly clean them between uses, they can make us sick, too. "If thermometers are not disinfected correctly, germs and bacteria can be spread including viruses such as those that cause the common cold and influenza, as well as COVID-19," says Dr. Paul Sherman, chief medical officer at Community Health Plan of Washington. "It's also possible to transmit bacteria such as those that cause strep throat or Methicillin-resistant Staphylococcus aureus (MRSA) infections. It's not worth taking the chance with any of these infections."
Fortunately, with the right techniques, you can quickly clean and disinfect any type of thermometer to ensure it stays germ-free.
First, check the manufacturer's instructions.
Whenever possible, Dr. Sherman says it's best to first check the manufacturer's instructions for cleaning your thermometer to ensure you won't cause any damage. "Digital components of modern thermometers may or may not be waterproof," he explains. "You can find these directions in the original box or search online for the manufacturer's web page, where they will have an online version of the recommended cleaning instructions."
How to clean and disinfect traditional stem thermometers.
For thermometers that enter the mouth or body, such as mercury thermometers or digital pacifiers, Dr. Sherman says you should first rinse the tool in cool water to remove any excess saliva or other debris. "Then rub the device with at least 70-percent isopropyl alcohol (the active ingredient in rubbing alcohol) that has been poured onto a clean cloth or cotton ball," he says.
How to clean and disinfect touch thermometers.
If you've just used a touch thermometer, like those that scan the forehead or go into the ear, Dr. Sherman says that a little rubbing alcohol will get the job done in no time. "Rub with at least 70-percent isopropyl after each use," he advises. "Both thermometers that enter the body and touch thermometers should be cleaned after every use."
How to clean and disinfect no-contact (infrared) thermometers.
Even though infrared thermometers, which measure body temperature from a distance, don't require direct contact, Dr. Sherman says they still need to be cleaned and disinfected in certain cases. "Since these devices don't make contact with each individual, they do not need to be cleaned as frequently if you are only testing yourself," he explains. "However, they should be disinfected with at least 70-percent isopropyl before they are passed by hand between person to person."
Can hand sanitizer effectively clean and disinfect a thermometer?
Although it isn't ideal, Dr. Sherman says hand sanitizers or disinfecting wipes can be used to clean a thermometer in a pinch. "While hand sanitizer often does the job, not all hand sanitizers contain at least 70-percent alcohol, which is the official recommendation for disinfecting thermometers," he explains. "Also, many hand sanitizers also contain additives like aloe or perfumes, which are not beneficial for these surfaces. However, if hand sanitizer or a disinfecting wipe is all you have, these products are better than not disinfecting the thermometer altogether."