The FEV1/FVC ratio is a calculated ratio used in the diagnosis of obstructive and restrictive lung disease.[1][2]
It represents the proportion of the forced vital capacity exhaled in the first second[3].
Normal values are approximately 80%.[4]
Disease states
In obstructive lung disease, the FEV1 is reduced due to obstruction to air escape. Thus, the FEV1/FVC ratio will be reduced[5].
In restrictive lung disease, the FEV1 and FVC are equally reduced due to fibrosis or other lung pathology (not obstructive pathology). Thus, the FEV1/FVC ratio should be approximately normal[6].
References
- ^ Swanney MP, Ruppel G, Enright PL, et al (December 2008). "Using the lower limit of normal for the FEV1/FVC ratio reduces the misclassification of airway obstruction". Thorax 63 (12): 1046–51. doi:. PMID 18786983. http://thorax.bmj.com/cgi/pmidlookup?view=long&pmid=18786983.
- ^ Sahebjami H, Gartside PS (December 1996). "Pulmonary function in obese subjects with a normal FEV1/FVC ratio". Chest 110 (6): 1425–9. PMID 8989055. http://www.chestjournal.org/cgi/pmidlookup?view=long&pmid=8989055.
- ^ http://www.gp-training.net/protocol/respiratory/copd/spirometry.htm
- ^ "Forced Expiration". http://oac.med.jhmi.edu/res_phys/Encyclopedia/ForcedExpiration/ForcedExpiration.HTML. Retrieved on 2009-04-21.
- ^ http://www.gp-training.net/protocol/respiratory/copd/spirometry.htm
- ^ http://www.gp-training.net/protocol/respiratory/copd/spirometry.htm
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