Don't Use the "Float Test"

I was on a call with a group of nurses, when one of them mentioned something about using the "float test" to see if an inhaler was full. 

I had just been listening to the call up to that point, but knew I HAD to say something. As a Certified Asthma Educator (AE-C), I am ethically bound to make sure people have correct information. And - to correct any misinformation. 

And that included the float test. 

What is the "float test?"

Well, decades ago (literally), inhalers didn't have counters on them, so it was hard to know how many puffs were left. 

So, people were supposed to take the metal canister out of the holder, and put it in water to see if it floats. The idea was that if floated, it was supposed to be empty.

But a study from the National Institutes of Health way back in 2002 said that:

"Float characteristics are product-specific and a function of canister size, design, content, and method of testing. Clinicians and asthma educators should not advise patients to use a float test to assess the amount of medication remaining in an MDI."

Consumer Safety (back in 2004), said:

"Some people also believe that an empty inhaler will float, but this is not a reliable test. You can get different results depending on whether the stem of the inhaler is up or down in the water. Also, some inhalers will float when they are full."

 The three most common rescue inhalers are:

ProAir (notice the counter?!)

 Ventolin (also has a counter!)

This photo is from the manufacturer's website and shows that it has a counter. 

Proventil (now has a counter!) 

This is from the manufacturer's website and you can clearly see this one has a counter on the top. 

So, what have we learned today? All rescue inhalers have counters, and most controller inhalers have counters. 

So, look at the counter. 

Do NOT use the float test!!!