Why qualitative testings no longer fit

Quantitative is taking over for good reason

Updated July 9, 2026
By Blue Print Editorial Team

“Hundreds.” That was the answer when we asked our safety team if they had done any qualitative fit testings. Turns out they’ve visited lots of customer sites and worked with many of their employees within a respiratory program. It goes without saying, the importance of ensuring a mask fits well and provides the necessary protection is essential to the basic drive we all share and that is, simply stated, to keep our employees safe each day.

The bonus to this test method was the reaction of the employee as the tests began. The general vibe was that it was always a little fun to see the faces of those that tasted the Bitrex as it hit their tongue during the pre-test test. The qualitative fit testing method had always been preferred due to its speed.

But the team says testing has evolved. We know now the qualitative tests are very subjective and can be influenced by things like an employee smoking minutes before the test or if they had coffee just before walking into the room. So, clearly, there are limitations to qualitative fit testing. If you get a moment, read through the Safety+Health article, “The limitations of qualitative respirator fit resting,” dated Jan. 1, 2001, authored by Jeff Weed. Within the article he notes the following.

• “Properly designed qualitative protocols include a threshold sensitivity test that each person must pass prior to being fit tested to ensure that he or she can detect the very low in-mask concentration that results when the fit factor is just below 100. If a person cannot pass the threshold test, that qualitative fit test method cannot be used.
• Most people have the ability to sense 1/100 concentrations, but the percentage of people who can reliably sense lower concentrations such as 1/500 or less drops off quickly. Because of this, it is unlikely that a qualitative fit test method will ever be developed for a pass level of 500 or higher.”

Let’s revisit the initial thesis: Qualitative fit testing methods no longer belong with a best-in-class respiratory program. At Fastenal, our Safety Services Division offers to customers quantitative fit testing, using PortaCount devices. With these units, we can accurately quantify the fit factor required by a customer’s respiratory program without having to rely on the subjectivity of an employee.

Upon completion of a testing session, we provide a premium test method to ensure the employee is returning to the production floor FIT for duty. As technology and time move forward, we need to follow them. Trusting the metrics of quantitative testing is one way we can do that. Reach out to us to find out how: [email protected].

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