Dr. David Chim

Family Medicine Department


Checking how well your lungs are functioning (by something called “Pulmonary Function Tests”) is very helpful in many clinical situations.  This is especially true when an individual has symptoms of lung disease, or when he or she gets exposed to a lot of air pollutants (the air quality reports in China can be quite alarming).


So what exactly are Pulmonary Function Tests (PFTs)?  PFTs have techincal medical names: let’s focus on “spirometry” and “spirometry before and after a bronchodilator.”

If you happen to already use an inhaler prescribed by your doctor, please don’t use it for four hours before the PFTs.  For other medications, please consult with your physician about how long you should not use them before your PFTs.


Let’s re-focus on “spirometry.”  It measures how much air is exhaled at a specific time point (e.g. one second) during a strong and complete exhalation--after you take a deep breath in, of course. This gives the clinician a lot of information when visualized on a graph.  The test itself should only be about 15 minutes—but the interpretation of the results will need more time.


Spirometry is usually enough to help diagnose asthma, but if we are looking for something like chronic obstructive pulmonary disease (COPD) then it needs to be done before and after inhaler (aka “bronchodilator”) use.  We won’t go into too many details here but know that’s how doctors evaluate air flow in your lungs--to check on symptoms like those coughs that don’t go away.


Breathing in Shenzhen