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British Lung Foundation
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FEV1/FVC percent 66 %

I used to get a lot of COPD exacerbations - After stopping smoking they got less. After stopping smoking my FEV1/FVC percent rose to the 90% range, Stranhe it had gone from under 50% to over 90%.

However it peaked and in 2 years has gone back to 66% - I am reading this from my medical record on line.

17 Sep 07FEV1/FVC percent56 %

03 Dec 14FEV1/FVC percent84 %

09 Aug 17FEV1/FVC percent66 %

Just three samples I have copied and pasted.

My question is - FEV1/FVC percent66 % mild or moderate?

Above is a sample of how low mySPO2 can go, rare so low but does happen. i only posted the pic as Dr said it was related to COPD at a time when my FEV1/FVC % was not that low.

11 Replies


Subject to the Fev and FVC

The ratio FEV1/FVC will indicate the type of condition 69% or lower indicates a obstructive lung condition.

Not the severity, which is indicated by your FEV1%

Stage 1 = 80% – mild COPD (able to achieve normal results after medication)

Stage 2 = 50-79% – moderate COPD

Stage 2 = 30-49% – severe COPD

Stage 4 = less than 30% – very severe COPD


Fev1/FVC is just bit below 0.7 (70%) is likely only mild obstruction.



A good clear and understandable answer Stone. Like myself,initially, there seems to be many people who are so confused about spirometry readings. The general procedure seems to be that an individual is told that they have copd, and are then given a print out of spirometry results with no explanation. This seems to prompt consultations with Dr google to find out, which terrifies, and describes terrible case scenarios. Why the person diagnosing cannot take a little time to explain things is beyond me.It would prevent so much stress and anxiety. I had asked 2 Gp's and a specialist and was pretty much fobbed off. I was confused for months until it was explained to me on here. This site is brilliant and it would be great if everyone when first diagnosed were made aware of it in primary care. Carolx

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Hi Carol - I totally agree. However I change doctors and the equipment was different.

With stones answer "Stage 2 = 50-79% – moderate COPD" it was seem my COPD is moderate as my result was FEV1/FVC percent66 %.

However when reading on my Drs Medical records I see.

"Peak expiratory flow rate measured using EN 13826 device252 L/min " - is that a Peak Flow meter result?

"Forced vital capacity - FVC2.5 litre"

"Forced expired volume in 1 second1.67 litre"

Clear as mud. However with all the tests, there is a graph at the side which showed a very marked improvement when I stopped smoking - The trend over the last 5 years is going backwards to the bad old days, even though I have not smoked for 12 years or more.

My CKD, Heart and TF test are all easier to understand than the COPD tests, they are baffling.


Hi Stone I’m going over old posts and was curious what is meant by “the type of condition” as far as ratio FEV1/FVC ? Thanks



You lung condition is either Obstructive or Restrictive.


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Thank you


Hi Em, your fev1/fvc, in your case 66% represents that you have an obstructive lung condition because it is below 69%,not the severity of it. The seveverity of your condition is determined by your fev1%. Carolx


I asked my GP to work out the figures for me and he said i had 23% projected capacity remaining. Not good and very severe of course. Hey-Ho a day at a time. No infection today and coping.


Keep well trough the winter. I am not sure how much lung capacity I have left.but i doubt as small as yours. i do have Angina and Brady/tacky syndrome and together they are a pain. but hey ho - one day or month at a time, the best attitude.


My understanding is that most physicians go by the Fev1 results. If you feel your Fev1 is deteriorating quickly would it be a good idea to ask for a respiratory physician appointment and a CT scan to see why this is happening ? Hope you get some answers. As mentioned by Stone the Fev1 score determines what stage of COPD you are.


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