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How Viruses (like COVID-19) Can Affect Qualitative Respirator Fit Testing Results

The Qualitative Respirator Fit Test is a method that relies on the ability of the test subject to detect a challenge agent such as Saccharin. It has been in use for decades and predates the evolution of Quantitative Fit Testing methods and equipment.

Qualitative testing assumes that if any amount of the challenge agent penetrates the respirator/face seal the test subject will taste or smell it. The test is conducted while the test subject is wearing a hood into which the challenge agent is aerosolized. There are several factors associated with this method which can and have been proven to occur, chief among which are:

  1. Extreme variations in different subjects’ ability to taste or smell the challenge agent
  2. Truthfulness or confusion of test subjects in reporting whether or not they can sense the challenge agent
  3. Onerous physical requirements in the protocol and now, continuous decontamination between tests which tend to encourage “short cuts” in the execution of the test, and
  4. The complete lack of any defensible metric such as the Fit Factor data that is collected and recorded by the Fit Test device when performing a Quantitative Fit Test.

The first concern, that of the wide variation in the test subjects’ ability to detect the challenge agent, is exacerbated by the generally recognized fact that many persons who are infected with the SARS CoV-2 virus which causes Covid-19, even if asymptomatic, can experience greatly reduced olfactory sensitivity. One can easily imagine a situation in which an asymptomatic but infected individual would be tested by using a challenge agent for which they have a greatly reduced ability to sense.

A 2020 article in Scientific American by Leslie Kay, Ph.D. addresses both the mechanism of this olfactory dysfunction and the fact that it can exist in asymptomatic individuals.

The concern is that the already-problematic qualitative test now has another reason to distrust the results; virus-induced olfactory dysfunction (medical term: Anosmia).

A Quantitative Fit Test using the new streamlined OSHA 2019 standard can be conducted in about two and a half minutes.  The results are completely objective, produce a defensible metric, and are not affected by any impaired sense of taste or smell.

NIH recently released this information which presents a very serious statistical evaluation of the reduced sense of smell in the population of the US.

An infographic summarizing information and statistics on the sense of smell in U.S. adults over age 40.

For more information about the advantages of Quantitative Fit Testing compared to Qualitative, please feel free to contact us here.

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