Fit Testing in the NHS


Fit Testing is carried out to assess whether a given respirator is suitable for a given individual. Fit Testing in the UK is primarily carried out using two distinct methods: the qualitative fit testing method (QLFT), and the quantitative fit testing method (QNFT).


Qualitative Fit Testing (QLFT)

The qualitative fit testing method tests whether the subject can taste a strong flavoured aerosol solution through potential gaps between the subject’s face and the seal of the respirator.

  • Basic pass/fail test.
  • Subjectively based on the ability/opinion of the subject to taste the challenge agent.
  • Heavily reliant on the trainer to administer the test correctly and can be very time consuming.
  • Failure by the tester could result in a false positive result – meaning the subject passes on a respirator that does not fit.

Full Support does not endorse this method of fit testing.


Quantitative Fit Testing (QNFT)

The quantitative fit testing method measures and compares the number of particles inside and outside the respirator when worn, using a specialist piece of machinery, to objectively assess the suitability of the seal.

  • Gives an accurate level on how well the respirator fits (fit factor).
  • Objectively measured through specialist equipment and not reliant on the wearer’s judgement.
  • Easy to set up and administer with on-screen instructions. Quick and reliable.
  • Failure by the tester could result in a false negative result – meaning the subject fails the test and would have to try again.

Full Support fully endorses this method of fit testing.


For more information on fit testing, PPE or RPE, get in touch with one of our fit2fit accredited trainers today.