Overview :

The FEV3-to-FVC Ratio is the volume of air expired in the first 3 seconds, expressed as a percentage of FVC.

FEV3-to-FVC ratio =

= (FEV in first 3 seconds of expiration) / (FVC) * 100%

FEV3 to FVC ratio in percent for White males 15 - 91 years of age (Crapo, 1981) =

= ((-0.0627) * (height in cm)) - (0.145 * (age in years)) + 112.09

FEV3 to FVC ratio in percent for White females 15 - 91 years of age (Crapo, 1981) =

= ((-0.0937) * (height in cm)) - (0.163 * (age in years)) + 118.16

Crapo RO, Morris AH, Gardner RM. Reference spirometric values using techniques and equipment that meet ATS recommendations. Am Rev Respir Dis 1981; 123:659-664.

Fishman A (editor). Pulmonary Diseases and Disorders, Second Edition. McGraw-Hill Book Company. 1988. page 2483