How do you know if a Healthcare Facility is clean?

A big area of focus since the COVID-19 pandemic is the cleanliness of our healthcare facilities. But one question came up during the pandemic. How do we know if a healthcare facility is clean? As Peter Drucker famously said, “If you can’t measure it, you can’t manage it.” The great news is there is a way to measure the cleanliness of a facility, and with advances in technology, it is becoming easier and more accurate every day.

The main tool used in measuring the cleanliness of a facility is called a luminometer. This is a device that measures how much light comes out of a sample. Whoooooo, light out of a sample? What are you talking about?

Let us take a quick look at chemistry. In this world, there are different ways to produce light or luminescence. You can produce light by passing electricity through a molecule, exciting the molecule to a point where it emits light. This is called electroluminescence and we see this in fluorescent light bulbs. In nature we see another example of luminescence called bioluminescence.  This is seen in the physiological reaction that causes the glowing tails of fireflies at night.

Another way to create light is through chemiluminescence. This is where chemicals come together and create a reaction, the byproduct being light. A fun example most people are familiar with is glow sticks. When you snap a glow stick you are creating a chemical reaction between hydrogen peroxide and a chemical called diphenyl oxalate, and you get a glow. Kids love them and they are used for 4^th of July parties everywhere.

On a more serious note, an example of chemiluminescence that pertains to infection control is the reaction of ATP and a compound called luciferin.  When you mix these chemicals it also produces light.  ATP is an energy molecule found in all living cells. When cells die, they leave behind these molecules on surfaces. Microorganisms can feed on these molecules and spread throughout a facility. For more information on ATP read this article: “What is ATP? And Why is it important?”

If you take a swab and wipe a surface, the ATP on the swab, combined with luciferin in a chemical reaction, will produce light. The more ATP that is present on the sample the brighter the reaction will glow. This glow or luminescence is measured in units called relative light units or RLU for short.

So, let’s get back to the main question of what is a luminometer. This is a device that detects luminescence as measured by RLUs. Like many scientific devices, the design of luminometers has evolved over the years. They used to be big machines that sat in laboratories, and there are still some of those out there. But the design of these devices has advanced to the point where some are about the size of a smartphone and are very portable.

There are also different types of luminometers as well as different ways to deliver the luciferin to a sample to generate the luminescence. We won’t go into all the details on those items but know there is a whole world of luminescence out there around tools that can measure light.  If you are interested in learning more, click here to read a paper comparing the different types of luminometers and showing the pros and cons between different models.