It's now really a peak flow. Similar but much more complex.
Its called a Spiromtery exam. You will do 2 types of tests with 3 go's at each.
The first will measure your total lung capacity co you take a massive deep breath then blow into the machine until literally every single gasp of air is out of your lungs.
The second measures how quickly you can deplete the air in your lungs. You basically do the same as the first test but this time you do it as quickly as possible. Can't remember what I got but it was pretty good. Having said that, going to the gym 5 times a week helped this bit for me being an ex smoker.
Hope this helps.
CS
