Demystifying N95 Mask Fit Testing: A Guide for Healthcare Professionals

In healthcare, personal protective equipment (PPE) is a frontline defense. Among PPE, the N95 respirator stands out for its ability to filter airborne hazards. But did you know that even the best N95 mask is only effective if it fits properly?

What Is N95 Mask Fit Testing?

Mask fit testing is a process that ensures a specific make, model, and size of N95 respirator forms a proper seal on the wearer’s face—vital for effective protection in healthcare settings.

There are two main methods, but they’re not created equal:

  • Qualitative Fit Testing:
    This approach uses the wearer’s ability to taste or smell a test agent (like a bitter or sweet aerosol) to detect leaks. While common, it’s subjective and, according to industry data, only results in a 57% pass rate.
  • Quantitative Fit Testing (SCL Group’s Method):
    Quantitative fit testing is the gold standard. It uses specialized equipment to objectively measure the amount of air leaking around the mask’s seal. This method provides clear, numerical results—removing guesswork entirely. At SCL Group, we exclusively use quantitative fit testing because it delivers a 99.1% pass rate, ensuring the highest level of protection for staff and patients alike.

Why does this matter?
Quantitative testing doesn’t rely on personal perception or taste—it’s precise, consistent, and scientifically validated. That means healthcare professionals can trust their mask is working as intended, every single time.

Why Is Fit Testing Required?

  • Regulatory Requirement: In Ontario (and across Canada), fit testing is mandatory for healthcare staff who may be exposed to airborne hazards.
  • Safety: An improper seal means the mask can’t filter out harmful particles, putting both staff and patients at risk.
  • Changing Faces: Weight changes, dental work, or facial hair can all impact mask fit over time.

What Happens During a Fit Test?

  1. Education: Staff learn about the importance of fit and how to check their seal daily.
  2. Testing: The chosen mask is tested for fit using standardized procedures.
  3. Troubleshooting: If a mask doesn’t fit, alternatives are tried until a proper seal is achieved.
  4. Documentation: Results are recorded for compliance and future reference.

How Often Should Fit Testing Be Done?

Regulations typically require fit testing:

  • At least every two years
  • Whenever there’s a change in facial structure (e.g., significant weight change, dental surgery)
  • If a new mask model is introduced

Tips for Healthcare Teams

  • Schedule ahead: Fit testing can often be completed in under 10 minutes per person, but it’s helpful to plan sessions around shift changes.
  • Be proactive: Encourage staff to report changes that might affect mask fit.
  • Keep records: Proper documentation helps with compliance and future audits.

The Bottom Line

Mask fit testing is a simple but essential part of workplace safety in healthcare. It’s not just about ticking a box—it’s about ensuring every person is truly protected when it matters most.