Chronic Obstructive Pulmonary Disease (COPD) Expert Forum
Pulmonary Function Test
About This Forum:

This forum is for questions and support regarding COPD, coughing/wheezing, chronic bronchitis, emphysema, lung infections, pollution, smoking, treatment for COPD and what causes COPD.

Font Size:
This expert forum is not accepting new questions. Please post your question in one of our medical support communities.
Blank Blank

Pulmonary Function Test

Spirometry results (see below for context):
(Normals: Knudson)
VC 111% of predicted (pre) and 115% (post-bronchodilation)
FVC 118% of predicted (pre) and 114% (post-bronchodilation)
FEV1 103% of predicted (pre) and 110% (post-bronchodilation)
FEV1/VC .76 (versus .82 predicted) and .79 (post-bronchodilation)
FEV1/FVC 72% (versus .83 predicted) and .80 (post-bronchodilation)
*The computer generated "Prediction Quadrant" at the bottom of my spirometry report put me on the borderline for obstructive pre-bronchodilation and in the normal range post-bronchodilation.

I'm not sure how to interpret these results (and I think my doctor is not sure either since at my first appointment after the test he referred to it as a "normal" spirometry result and then at the next appointment when I asked him about the prediction quadrant saying there was obstruction, he said "Well, it does suggest minor obstruction."

I'm puzzled because based on what I've read online, my numbers don't seem to qualify for COPD (unless I'm misunderstanding something), though perhaps my pre-bronchodilation FEV1/FVC of 72% is below the Lower Limit of Normal?  However, if they indicate obstruction I didn't have enough of a bronchodilator response to "qualify" for asthma.  My FEV1/FVC went up 8% with bronchodilation, less than the 9%-12% improvement suggestive of asthma, though I did have a 200+ml FEV1 improvement post-bronchodilator.

I read somewhere that if your FEV1 and FVC are both in the normal range that your FEV1/FVC ratio does not matter. Is that true? (

I'm hoping to rule out COPD with this spirometry.  Can anyone interpret my numbers for me.  Thanks!!!

Your PFT’s test results are not consistent with the diagnosis of COPD.  They are consistent with but not diagnostic of asthma.  
I read somewhere that if your FEV1 and FVC are both in the normal range that your FEV1/FVC ratio does not matter. Is that true?
That is incorrect.  So-called normal values are Mean Values.  For a given individual his/her normal values may have exceeded the predicted values by 25% or more.  In this circumstance, both FEV1 and FVC could be in the normal range with an actually low FEV1/FVC, indicative of obstructive lung disease, asthma or COPD.

Your test values are consistent with the diagnosis of asthma as is your cough.  With so-called cough-variant asthma, routine PFT’s may actually be within the normal range.

A Methacholine challenge might be helpful in establishing the diagnosis.

Good luck
I'm a 33 year old non-smoker. I was exposed to second-hand smoke as a child.

At the age of 13 I was diagnosed with exercise-induced asthma and given a puffer, which I used a little bit for a few months, but not again.

For the past 10+ years I've had a chronic cough, which I always thought was allergy related.  Nine years ago I started allergy shots, which helped the cough, but still it never went completely away.

Over the past three or four years I've begun to notice minor breathing issues, particularly in hot, humid weather.

I recently went to the doctor to try to find a cure for the chronic cough and occasional breathlessness and did a spirometry test (see previous post).  I also had a chest x-ray, which came back normal.

To clarify, in the original post my pre-bronchodilator fev1/fvc% was 72.
Expressed as a ratio, my fev1/fvc then was .72 (prebronchodilation)
Thanks so much David.

What would a spirometry result consistent with COPD look like?  I've read that a post-bronchodilation FEV1/FVC% below 70% is consistent with COPD.

Is that the standard that you look for?

Do you consider the post-bronchodilation (as opposed to the pre-bronchodilation) FEV1/FVC% the key value in determining COPD (as it shows the reversibility of any obstruction)?

You said that my spirometry and symptoms were consistent with cough-variant asthma.  I had read that for asthmatics the post-bronchodilation improvement would tend to be more exaggerated than mine was.  

So, you are saying that a change (pre- to post-bronchodilation) of less than 9-12%+ for the FEV1 can still be asthma?

The most confusing part of my symptoms is the fact that I don't cough during the night.  My doctor seemed to think that means my cough is a "habit cough."  The reading I've done has pointed to perhaps a reflux-related cough.  

Is it possible to have a "pseudo-asthma" that shows up on "borderline" spirometry like mine that is caused by mucus related to so-called silent reflux (also known as LPR, a variant of GERD)?  

I read somewhere that some people's asthma is cleared up when their GERD or LPR (reflux) is treated effectively.  Is that possible?

Could my spirometry improve to be normal pre-bronchodilation if I did have GERD and it was treated effectively?

The reason I am thinking that reflux could be contributing to the cough and breathlessness is that I tend to cough more after eating and when sitting down (in an upright position) or leaning forward.  I tend to cough less when walking versus sitting and (as I mentioned earlier).  Moreover, the breathlessness I experience tends to be more when sitting upright after a meal.

Perhaps I could have both cough-variant asthma and a form of reflux both causing these symptoms.

Thanks again, David, for your response. (Sorry for so many questions!)  It's great to get answers from a professional like yourself.

More details: My doctor has put me on Pulmicort Turbuhaler (2X daily for a six week trial).  At my next appointment I'm thinking of asking for a referral to an ENT specialist.  I'm already scheduled to see an allergist in the fall.

One more question, David:
Is my pre-bronchodilation spirometry normal? Or is my pre-bronchodilation FEV1/FVC% of 72 outside of the normal range? Most discussions I've read have said that an abnormal spriometry would include a post-bronchodilation FEV1/FVC% below 70.

I haven't seen much about pre-bronchodilation values, other than mentions of the relevance of % improvements (post-bronchodilation) in FVC and FEV1 in diagnosing asthma.

You said that an individual could have cough-variant asthma with a normal spirometry (because with asthma obstruction varies).  

Thanks again for your help and answers!
To simplify, in the post above, what I'm really asking is was my doctor accurate when he described my (pre- AND post-bronchodilation) spirometry as being "normal"?

(Though as you mentioned in the case of cough-variant asthma a routine PFT could be normal.)
Request an Appointment
Asthma Tracker
Asthma Tracker
Start Tracking Now