All tests › Breathing tests
FEV1/FVC ratio
Typical UK adult range70 % and above
What this test measures
The ratio of FEV1 to FVC shows what fraction of the total breath can be blown out in the first second. A low ratio points to narrowed airways.
Why doctors request it
The key spirometry number for telling airway narrowing (obstruction) from stiff lungs (restriction).
What commonly pushes it up
- Stiff lungs can push the ratio up, because both numbers fall but FVC falls more
What commonly pushes it down
- Asthma and COPD
- Increasing age, gently
Everyday reasons for a value outside the range
- The ratio falls naturally with age, so a fixed 70 percent cut-off over-reads in older people; some labs print a lower limit of normal instead
- A poor blow can go either way
About the sample
Read with the absolute values.
Got a report with FEV1/FVC ratio on it?
Upload a photo or PDF and see every line against the range your lab printed, explained in plain English. First report free.
Read my report freeThis is an educational summary of results you uploaded. It is not medical advice, a diagnosis or a treatment plan, and it does not replace the doctor who requested the test. If you are worried, or a result is marked outside range, discuss it with your doctor. Written and reviewed by a UK consultant physician. Reference ranges vary between laboratories.