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Table of Contents
Purpose
Risks and Contraindications
Interpreting Results
The FEV1/FVC ratio is a test that helps measure how much air you can forcefully expire (exhale) from your lungs. It involves a tool called aspirometerthat can deliver two specific measurements:
The test can help diagnose and monitor restrictive lung diseases (in which you have difficulty inhaling) or obstructive lung diseases (in which you have difficulty exhaling).
This article discusses the purpose of the FEV1/FVC ratio and its use in diagnosing and treating lung diseases. It also explains how the results are interpreted and what follow-up tests may be needed.
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Purpose of FEV1/FVC Test
If you have been diagnosed with a pulmonary (lung) disorder, you will undergo a battery of tests, including the FEV1/FVC ratio. The FEV1/FVC ratio can help determine whether your condition isrestrictive or obstructiveand how severe the restriction or obstruction is.
This test can also monitor lung disease. Measuring your FEV1/FVC ratio at regular intervals can help assess how well treatment is working and whether your condition is progressing, improving, or remaining stable.
A Word From VerywellHeart and lung health are important predictors of longevity. Therefore, it’s important to understand how well your lungs are doing. By testing how well you can inspire and expire, and how fast, you can create a wellness picture that determines if your lungs are functioning at their best or if they have some restriction or obstruction.—STEFFINI STALOS, DO, MEDICAL EXPERT BOARD
A Word From Verywell
Heart and lung health are important predictors of longevity. Therefore, it’s important to understand how well your lungs are doing. By testing how well you can inspire and expire, and how fast, you can create a wellness picture that determines if your lungs are functioning at their best or if they have some restriction or obstruction.—STEFFINI STALOS, DO, MEDICAL EXPERT BOARD
Heart and lung health are important predictors of longevity. Therefore, it’s important to understand how well your lungs are doing. By testing how well you can inspire and expire, and how fast, you can create a wellness picture that determines if your lungs are functioning at their best or if they have some restriction or obstruction.
—STEFFINI STALOS, DO, MEDICAL EXPERT BOARD
Restrictive Lung Diseases
Restrictive lung diseases are those that limit your ability to inhale due to reduced lung volume. Examples include:
Obstructive Lung Diseases
Obstructive lung diseases are those that reduce your ability to exhale due to obstruction or dysfunction of the airways. Examples include:
What to Expect From a Spirometry Test
Spirometry is a safe, non-invasive test. It involves breathing into a tube attached to a meter that measures the volume and/or force of airflow.
There are few side effects associated with spirometry. Some people may feel lightheaded, have shortness of breath, or cough when blowing into the spirometer. If you have asthma, there is a small risk of anasthma attack.
Spirometry may not be recommended in people with the following conditions:
The FEV1/FVC ratio is expressed as a percentage (%). A result is “normal” if the percentage is at or above the predictive value for your age, height, and sex.
Percentages below the predictive value are considered abnormal. The lower the percentage, the more severe the lung condition generally is.
By comparing the FEV1/FVC ratio to the total volume of air in your lungs (FVC), your healthcare provider can determine whether your condition is:
Normal FEV1/FVC Ratio and Normal FVC
At first glance, a normal FEV1/FVC ratio and normal FVC might suggest that you have no problem, and, in most cases, that would be right.
However, once-off spirometry doesn’t always expose conditions like mild to moderate COPD. In some cases, the FEV1/FVC ratio can veer between normal and abnormal values (referred to as “diagnostic reversals”). Some studies report that as many as one in five people with mild to moderate COPD fall within this category.
Because of this, repeated spirometry may be needed to return an accurate result.
People with asthma may also have a normal FEV1/FVC ratio as well as a normal FVC outside of an asthma attack. In such cases, a bronchoprovocation challenge may be needed to induce asthma symptoms with inhaled chemicals or cold air.
Decreased FVC
If your FVC is decreased but the ratio of FEV1/FVC is normal, this indicates a restrictive lung condition. Restrictive problems occur when a person can’t inhale deeply due to the loss of lung capacity.
In addition to restrictive lung diseases, a decreased FVC may be due to:
Decreased FEV1/FVC Ratio
A decreased FEV1/FVC ratio with a normal FVC indicates an obstructive lung condition. The diagnosis is usually reached when the ratio is less than 70% in adults and less than 85% in children.
Damage or dysfunction of the airways is associated with conditions such as asthma, COPD, bronchiectasis, or cystic fibrosis. Uncommon causes of pulmonary obstruction include:
Decreased FEV1/FVC Ratio and Decreased FVC
When both the FEV1/FVC ratio and FVC are decreased, it is a sign of a mixed defect involving obstruction and restriction.
This can occur when a long-standing lung disease like sarcoidosis causes scarring that distorts the airways while reducing the overall volume of the lungs.Overlapping restrictive and obstructive lung diseases can do the same.
A mixed defect may be the result of co-occurring pulmonary and non-pulmonary diseases (such as COPD andheart failure) which cause direct damage to the airways and indirect damage to the lungs.
Comparing Bronchiectasis, Bronchitis, and Pediatric Bronchiolitis
Assessing the Severity
If the FEV1/FVC ratio is found to be abnormal, the next step is grading the abnormality to determine the severity of the condition. The American Thoracic Society has set specific guidelines for this:
If the ratio improves with a bronchodilator, that means that the obstruction is at least partially reversible. This is usually seen with conditions such as asthma.
If the ratio does not improve with a bronchodilator, it may be irreversible, such as is often seen in COPD.
FEV1/FVC Ratio and Further TestsWith restrictive lung conditions, your healthcare provider may recommend more pulmonary function tests. For obstructive lung conditions, your healthcare provider may retest your FEV1/FVC ratio. With some conditions, like asthma, your ratio may improve after using a bronchodilator.
FEV1/FVC Ratio and Further Tests
With restrictive lung conditions, your healthcare provider may recommend more pulmonary function tests. For obstructive lung conditions, your healthcare provider may retest your FEV1/FVC ratio. With some conditions, like asthma, your ratio may improve after using a bronchodilator.
Summary
Your healthcare provider can use the FEV1/FVC ratio to help determine if you have a restrictive or obstructive lung condition.
If you have a restrictive condition, you may need more pulmonary function tests to help diagnose your condition. If your lung condition is obstructive, your healthcare provider may recommend using a bronchodilator. It is also possible to have a mixed defect in which there is both restriction and obstruction.
11 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Johnson JD, Theurer WM.A stepwise approach to the interpretation of pulmonary function tests.Am Fam Physician. 2014;89(5):359-66.Wan ES, Balte P, Schwartz JE, Bhatt SP, Cassano PA, Couper D,et al.Association between preserved ratio impaired spirometry and clinical outcomes in US adults.JAMA. 2021 Dec 14;326(22):2287-2298. doi:10.1001/jama.2021.20939.Ginde S, Bartz PJ, Hill GD, et al.Restrictive lung disease is an independent predictor of exercise intolerance in the adult with congenital heart disease.Congenit Heart Dis.2013 May-Jun;8(3):246–254. doi:10.1111/chd.12010Samhouri BF, Ryu JH.Underappreciated causes of obstructive lung disease.Lancet Respir Med.2023 Feb;11(2):e14. doi:10.1016/S2213-2600(22)00527-6American Lung Association.Spirometry.Coates AL, Graham BL, Mcfadden RG, et al.Spirometry in primary care.Can Respir J. 2013;20(1):13-21. doi:10.29262/ram.v66i1.536Quaderi S, Hurst JR.One-off spirometry is insufficient to rule in or rule out mild to moderate chronic obstructive pulmonary disease.Am J Respir Crit Care Med.2017 Aug 1;196(3):254–256. doi:10.1164/rccm.201703-0551EDCoates AL, Wanger J, Cockcroft DW, et al.ERS technical standard on bronchial challenge testing: general considerations and performance of methacholine challenge tests.Eur Respir J.2017;49(5):1601526. doi:10.1183/13993003.01526-2016Obi ON, Baughman RP.Mixed obstructive and restrictive ventilatory defect in sarcoidosis: a new phenotype?Chest. 2020 Nov;158(5):1816-1817. doi:10.1016/j.chest.2020.05.561Khalid K, Padda J, Komissarov A, et al.The coexistence of chronic obstructive pulmonary disease and heart failure.Cureus.2021 Aug;13(8):e17387. doi:10.7759/cureus.17387COPD Foundation.Diagnostic decisions: What is spirometry and why is it important?Additional ReadingGodfrey M, Jankowich M.The vital capacity is vital: Epidemiology and clinical significance of the restrictive spirometry pattern.Chest. 2016. 149(1):238-251. doi:10.1378/chest.15-1045Koo K, Yun H, Byeong-Ho J, et al.Relationship between forced vital capacity and Framingham cardiovascular risk score beyond the presence of metabolic syndrome: The fourth Korea national health and nutrition examination survey.Medicine.2015. 94(47):e2089. doi:10.1097%2FMD.0000000000002089
11 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Johnson JD, Theurer WM.A stepwise approach to the interpretation of pulmonary function tests.Am Fam Physician. 2014;89(5):359-66.Wan ES, Balte P, Schwartz JE, Bhatt SP, Cassano PA, Couper D,et al.Association between preserved ratio impaired spirometry and clinical outcomes in US adults.JAMA. 2021 Dec 14;326(22):2287-2298. doi:10.1001/jama.2021.20939.Ginde S, Bartz PJ, Hill GD, et al.Restrictive lung disease is an independent predictor of exercise intolerance in the adult with congenital heart disease.Congenit Heart Dis.2013 May-Jun;8(3):246–254. doi:10.1111/chd.12010Samhouri BF, Ryu JH.Underappreciated causes of obstructive lung disease.Lancet Respir Med.2023 Feb;11(2):e14. doi:10.1016/S2213-2600(22)00527-6American Lung Association.Spirometry.Coates AL, Graham BL, Mcfadden RG, et al.Spirometry in primary care.Can Respir J. 2013;20(1):13-21. doi:10.29262/ram.v66i1.536Quaderi S, Hurst JR.One-off spirometry is insufficient to rule in or rule out mild to moderate chronic obstructive pulmonary disease.Am J Respir Crit Care Med.2017 Aug 1;196(3):254–256. doi:10.1164/rccm.201703-0551EDCoates AL, Wanger J, Cockcroft DW, et al.ERS technical standard on bronchial challenge testing: general considerations and performance of methacholine challenge tests.Eur Respir J.2017;49(5):1601526. doi:10.1183/13993003.01526-2016Obi ON, Baughman RP.Mixed obstructive and restrictive ventilatory defect in sarcoidosis: a new phenotype?Chest. 2020 Nov;158(5):1816-1817. doi:10.1016/j.chest.2020.05.561Khalid K, Padda J, Komissarov A, et al.The coexistence of chronic obstructive pulmonary disease and heart failure.Cureus.2021 Aug;13(8):e17387. doi:10.7759/cureus.17387COPD Foundation.Diagnostic decisions: What is spirometry and why is it important?Additional ReadingGodfrey M, Jankowich M.The vital capacity is vital: Epidemiology and clinical significance of the restrictive spirometry pattern.Chest. 2016. 149(1):238-251. doi:10.1378/chest.15-1045Koo K, Yun H, Byeong-Ho J, et al.Relationship between forced vital capacity and Framingham cardiovascular risk score beyond the presence of metabolic syndrome: The fourth Korea national health and nutrition examination survey.Medicine.2015. 94(47):e2089. doi:10.1097%2FMD.0000000000002089
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Johnson JD, Theurer WM.A stepwise approach to the interpretation of pulmonary function tests.Am Fam Physician. 2014;89(5):359-66.Wan ES, Balte P, Schwartz JE, Bhatt SP, Cassano PA, Couper D,et al.Association between preserved ratio impaired spirometry and clinical outcomes in US adults.JAMA. 2021 Dec 14;326(22):2287-2298. doi:10.1001/jama.2021.20939.Ginde S, Bartz PJ, Hill GD, et al.Restrictive lung disease is an independent predictor of exercise intolerance in the adult with congenital heart disease.Congenit Heart Dis.2013 May-Jun;8(3):246–254. doi:10.1111/chd.12010Samhouri BF, Ryu JH.Underappreciated causes of obstructive lung disease.Lancet Respir Med.2023 Feb;11(2):e14. doi:10.1016/S2213-2600(22)00527-6American Lung Association.Spirometry.Coates AL, Graham BL, Mcfadden RG, et al.Spirometry in primary care.Can Respir J. 2013;20(1):13-21. doi:10.29262/ram.v66i1.536Quaderi S, Hurst JR.One-off spirometry is insufficient to rule in or rule out mild to moderate chronic obstructive pulmonary disease.Am J Respir Crit Care Med.2017 Aug 1;196(3):254–256. doi:10.1164/rccm.201703-0551EDCoates AL, Wanger J, Cockcroft DW, et al.ERS technical standard on bronchial challenge testing: general considerations and performance of methacholine challenge tests.Eur Respir J.2017;49(5):1601526. doi:10.1183/13993003.01526-2016Obi ON, Baughman RP.Mixed obstructive and restrictive ventilatory defect in sarcoidosis: a new phenotype?Chest. 2020 Nov;158(5):1816-1817. doi:10.1016/j.chest.2020.05.561Khalid K, Padda J, Komissarov A, et al.The coexistence of chronic obstructive pulmonary disease and heart failure.Cureus.2021 Aug;13(8):e17387. doi:10.7759/cureus.17387COPD Foundation.Diagnostic decisions: What is spirometry and why is it important?
Johnson JD, Theurer WM.A stepwise approach to the interpretation of pulmonary function tests.Am Fam Physician. 2014;89(5):359-66.
Wan ES, Balte P, Schwartz JE, Bhatt SP, Cassano PA, Couper D,et al.Association between preserved ratio impaired spirometry and clinical outcomes in US adults.JAMA. 2021 Dec 14;326(22):2287-2298. doi:10.1001/jama.2021.20939.
Ginde S, Bartz PJ, Hill GD, et al.Restrictive lung disease is an independent predictor of exercise intolerance in the adult with congenital heart disease.Congenit Heart Dis.2013 May-Jun;8(3):246–254. doi:10.1111/chd.12010
Samhouri BF, Ryu JH.Underappreciated causes of obstructive lung disease.Lancet Respir Med.2023 Feb;11(2):e14. doi:10.1016/S2213-2600(22)00527-6
American Lung Association.Spirometry.
Coates AL, Graham BL, Mcfadden RG, et al.Spirometry in primary care.Can Respir J. 2013;20(1):13-21. doi:10.29262/ram.v66i1.536
Quaderi S, Hurst JR.One-off spirometry is insufficient to rule in or rule out mild to moderate chronic obstructive pulmonary disease.Am J Respir Crit Care Med.2017 Aug 1;196(3):254–256. doi:10.1164/rccm.201703-0551ED
Coates AL, Wanger J, Cockcroft DW, et al.ERS technical standard on bronchial challenge testing: general considerations and performance of methacholine challenge tests.Eur Respir J.2017;49(5):1601526. doi:10.1183/13993003.01526-2016
Obi ON, Baughman RP.Mixed obstructive and restrictive ventilatory defect in sarcoidosis: a new phenotype?Chest. 2020 Nov;158(5):1816-1817. doi:10.1016/j.chest.2020.05.561
Khalid K, Padda J, Komissarov A, et al.The coexistence of chronic obstructive pulmonary disease and heart failure.Cureus.2021 Aug;13(8):e17387. doi:10.7759/cureus.17387
COPD Foundation.Diagnostic decisions: What is spirometry and why is it important?
Godfrey M, Jankowich M.The vital capacity is vital: Epidemiology and clinical significance of the restrictive spirometry pattern.Chest. 2016. 149(1):238-251. doi:10.1378/chest.15-1045Koo K, Yun H, Byeong-Ho J, et al.Relationship between forced vital capacity and Framingham cardiovascular risk score beyond the presence of metabolic syndrome: The fourth Korea national health and nutrition examination survey.Medicine.2015. 94(47):e2089. doi:10.1097%2FMD.0000000000002089
Godfrey M, Jankowich M.The vital capacity is vital: Epidemiology and clinical significance of the restrictive spirometry pattern.Chest. 2016. 149(1):238-251. doi:10.1378/chest.15-1045
Koo K, Yun H, Byeong-Ho J, et al.Relationship between forced vital capacity and Framingham cardiovascular risk score beyond the presence of metabolic syndrome: The fourth Korea national health and nutrition examination survey.Medicine.2015. 94(47):e2089. doi:10.1097%2FMD.0000000000002089
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