From the Guidelines
A fit test is a crucial procedure to ensure a respirator or mask forms a proper seal with the wearer's face, providing adequate protection against airborne hazards. The test evaluates whether the respirator fits correctly and prevents air from leaking around the edges. According to the guidelines for preventing the transmission of mycobacterium tuberculosis in health-care facilities, 1994, by the Centers for Disease Control and Prevention 1, fit testing is part of the respiratory protection program required by OSHA for all respiratory protective devices used in the workplace.
Importance of Fit Testing
- Fit testing determines whether a respiratory protective device adequately fits a particular healthcare worker (HCW)
- The HCW may need to be fit tested with several devices to determine which device offers the best fit
- However, fit tests can detect only the leakage that occurs at the time of the fit testing, and the tests cannot distinguish face-seal leakage from filter leakage 1.
- Currently available, cup-shaped, disposable particulate respirators have from 0 to 20% face-seal leakage, which can be reduced to less than 10% with improvements in design, a greater variety in available sizes, and appropriate fit testing and fit checking 1.
Types of Fit Tests
- Qualitative fit tests, which rely on the wearer's ability to detect a test agent (like a bitter or sweet solution) while wearing the respirator
- Quantitative fit tests, which use specialized equipment to measure the actual amount of leakage. Fit testing is required in many occupational settings where workers are exposed to harmful airborne contaminants, including healthcare facilities, construction sites, and industrial environments. The test should be performed initially before using a new respirator type and periodically thereafter, especially if the wearer experiences significant physical changes like weight fluctuation or dental work that might affect the seal 1.
From the Research
Definition of Fit Test
- A fit test is a procedure used to ensure that a respirator, such as an N95 mask, fits properly on an individual's face to provide adequate protection against airborne particles 2.
- The test is designed to verify that the respirator forms a tight seal around the face, preventing particles from entering the mask 3.
Importance of Fit Test
- Fit testing is crucial for healthcare workers who perform aerosol-generating procedures, as it helps prevent the transmission of airborne diseases such as COVID-19 2.
- A proper fit test can help reduce the risk of sickness leave and associated legal costs of compensation 2.
- Fit testing is also essential for optimizing the organizational structures of respiratory protection programs in healthcare settings 4.
Methods of Fit Test
- There are two main methods of fit testing: quantitative fit testing (QNFT) and qualitative fit testing (QLFT) 5.
- QNFT uses instruments to measure the amount of particles that enter the mask, while QLFT relies on the wearer's subjective sensation of taste or smell to detect leaks 6.
- Condensation nuclei counting (CNC) and controlled negative pressure (CNP) are two common methods used in QNFT 6.
Factors Affecting Fit Test
- Gender, age, and facial structure can affect the fit of a respirator and the outcome of a fit test 2, 6.
- Certain movements, such as talking or bending, can also affect the fit of the respirator and increase the risk of leakage 5, 6.
- The type of respirator used, including half masks and full masks, can also impact the fit test results 6.