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Overview :
The
FEV1-to-FVC ratio is the volume of air expired in the first second, expressed as
a percent of FVC.
FEV1-to-FVC
ratio =
=
(FEV1) / (FVC ) * 100%
FEV1
to FVC in percent for White males 15-91 years (Crapo, 1981) =
=
((-0.13) * (height in cm)) - (0.152 * (age in years)) + 110.49
FEV1
to FVC in percent for White females 15-84 years (Crapo, 1981) =
=
((-0.202) * (height in cm)) - (0.252 * (age in years)) + 126.58
FEV1
to FVC in percent for Hispanic males 25-75 years (Crapo, 1990) =
=(-0.1160
* (age in years)) + 86.5881
FEV1
to FVC in percent for Hispanic females 20-80 years (Crapo, 1990) =
=(-0.1862
* (age in years)) + 91.7259
FEV1
to FVC in percent for White males 65-85 years (Enright, 1993) =
=
(-0.294 * (age in years)) + 93.8
FEV1
to FVC in percent for White females
65-85 years (Enright, 1993) =
=
(-0.242 * (age in years)) + 92.3
FEV1
to FVC in percent for White males 18-86 years years (Roberts, 1991) =
=
(-21.476 * (height in meters)) - (0.242* (age in years)) + 126.252
FEV1
to FVC in percent for White females 18-86 years (Roberts, 1991) =
=
(-0.172 * (age in years)) + 88.134
Interpretation:
•
The FEV1/FVC ratio reflects the severity of pulmonary impairment in
obstruction.
|
FEV1 to FVC
ratio |
Interpretation |
|
>= 70% of predicted |
normal |
|
61 - 69% of predicted |
mild obstruction |
|
45 - 60% of predicted |
moderate obstruction |
|
< 45% of predicted |
severe obstruction |
|