Table 4.
Percentage of abnormal pulmonary function tests determined by the per cent predicted and percentile methods using Crapo et al (5–7) and Gutierrez et al (12) equations for men (n=2176)
| Parameter |
Conventional: Per cent predicted (Crapo/Gutierrez), %* |
Reference standard: Percentile (Crapo/Gutierrez), %* |
||
|---|---|---|---|---|
| Reduced | Increased | <5th percentile | >95th percentile | |
| FEV1 | 57.2/58.5 | – | 54.4/54.8 | – |
| FVC | 41.7/48.1 | – | 35.2/47.4 | – |
| FEV1/FVC† | 40.8/40.8 | – | 45.8/72.2 | – |
| TLC | 15.6/22.0 | 12.0/6.6 | 16.3/23.7 | 12.5/7.4 |
| RV | 14.7/19.5 | 30.5/26.0 | 7.3/6.5 | 36.9/28.4 |
| DLco | 47.7/35.8 | – | 52.8/29.9 | – |
*
Per cent predicted (reduced and increased) and the percentile (<5th and >95th) values are calculated using both the Crapo and the Gutierrez equations; they are reported here in the respective columns as Crapo/Gutierrez;
†
Abnormal ratio is <0.70 of actual FEV1/FVC. DLco Diffusing capacity of the lung for carbon monoxide; FEV1 Forced expiratory volume in 1 s; FVC Forced vital capacity; RV Residual volume; TLC Total lung capacity