Common Spirometry Testing Errors

Because spirometry is an effort dependent test, possibly the most important factor in acquiring accurate results is a motivated and enthusiastic staff to coach the patient before and during the test. It can take from 2-8 efforts (tests) in order to get good acceptable results prior to report generation and interpretation.

Common Reasons of Inaccurate Results are:


  • Lack of motivated and enthusiastic patient coaching
  • Failure of patient to take a complete inhalation prior to exhalation
  • Failure to request enough efforts from the subject to acquire their best effort
  • Patient stops exhaling too soon. Adults should exhale for a minimum of 6 seconds, children should exhale for at least 3 seconds
  • Patient obstructed mouthpiece with teeth or tongue
  • Slow test start. Patient didn’t “blast” the air out at the beginning of the test
  • Patient coughed during test

Testing Tip: Once you have had experience performing spirometry on your patients, you will develop your own best method for patient instruction and coaching. The following suggestions will assist in acquiring the best possible results from your patients.

  • Inform your patient. Prior to performing the test, explain to your patient that spirometry is an easy, pain-free test that simply measures how much and how fast they can exhale. Mention that it is not like blowing up a balloon, there is no resistance, it will feel like they are just blowing out into the room. Emphasize the fact that they will need to take the deepest breath possible, then hold it for a second, put the mouthpiece into their mouth keeping their teeth on the outside and make a tight seal around it with their lips. They will then BLAST the air out of their lungs as fast and as long as they possibly can. Tell them that it will feel like they have completely exhaled after 2-3 seconds, but that they actually still have air left over, so they should keep squeezing it out as long as they can. Let them know that when you hand them the spirometer that they can begin when they are ready and that you will help guide them through the maneuver.
  • Coach and Observe your patient. Once your subject understands how to perform the test, prepare the spirometer, then hand it to your subject. Now walk them through the test using encouraging body language. “Ok whenever you’re ready, take the deepest breath you possibly can, put the mouthpiece in your mouth, now “blast” the air out, keep going, keep going, keep going. Great job! Once the subject performs their first test, they’ll know what to expect and will typically perform better on their subsequent efforts. While coaching them, concurrently check for compliance and errors so that you can reinforce the correct technique prior to running the next effort.

Spirometry Reimbursement Increases for 2023!