British Lung Foundation
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where can i see the fev1 in the spirometry result?

hi ma'am jo! good day! my name is mark. im 35 yrs old. 3 yrs ago i had pneumothorax(collapsed lung) and my doctor told me that i have emphsyema. like everyone else here, i am also very much concerned abt life expectancy when u have this kind of disease. i get chest pains most of the time and have anxiety attacks. last week was my first time to try spirometry. i would like to ask if the fev1 is different from the fev1/fvc?

my fev1/fvc is 76%. dont know where to locate my fev1. im not sure if this is the one it says pre-rx %pred 94? im not sure if the 94 is my fev1.

thank u!

5 Replies

Hi Mark

With the best intentions, quite a lot of inaccurate stuff can get posted on here.. and eventually confuses people, so always best to include a link:

Fev1 (Forced Expiry Volume) is the volume of air that you can blow out in 1 second.

FVC (Forced vital capacity) is the volume of air that can forcibly be blown out after full inspiration.

Normal = should be able to blow 80% (arguably) of your total (FVC) capacity in 1 second.

Fev 1 is measured in litres ( so 2 or 3 or thereabout). If big number 25, 40, 60, 80 etc that is % of predicted (expected from 'normal lungs').

Men have significantly bigger lungs, and so different norms, than women. So:

Predicted numbers is an average of normals of your sex, that include big people with small lungs and small people with big lungs. So taken by itself Fev1 could look 'obstucted' because your blow is less than average... but you could have smaller than average lungs thus actually be normal!

Whilst someone else could blow 90% predicted but have bigger than average lungs and actually be obstructed.

So they need to take into account the size of your own lungs hence the ratio of blow(FEV1) to volume (FVC) where Fev1 divided by FVC (FEV1/FVC) = 75%, arguably, is bottom of the normal range, or top of the obstructed.. depending on age, and depending of history, smokers likely to be deemed obstructed.

There is another measure that tells where the obstruction occurs. I fail on the last quarter of the FVC blow (FEF 25-75) which indicates small airway obstruction. See link

So the good news is your spiro was borderline normal, but prob low for your age. And you had symptoms otherwise you wouldn't need spiro?

Did you have a CT scan?


thank you soooo much soulsaver for your time explaining this to me. i appreciate it a lot!!! pls correct me if i am your telling me that the normal average % of the fev1/fvc should be at least 75%?

how will i know or where can i see in my spirometry result that i blew 80% of my total fvc capacity in 1 second, is this the one saying fev1 pre-rx %pred 94?

thank you so much!


Yep that looks like it, but should also show a capacity - so, like, 4.20 litres. And makes sense as that would be in the normal range for average size lungs.


thanks so much my friend! this has helped me a lot specially with my anxiety. i thought all the while that i blew only 76% of my total fvc capacity in 1 sec. thanks for the info!!! god bless!


yes it says

fev1: 4.24 pred

pre-rx best 4.01

pre-rx pred % 94

post-rx best 4.24

post-rx pred % 100


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