The VA rates many respiratory conditions based on the results of pulmonary function tests (PFTs). Understanding which values the VA uses and how they translate to ratings is essential for veterans with breathing conditions.
The key PFT values are: FEV-1 (Forced Expiratory Volume in 1 second) — the amount of air you can forcefully exhale in one second; FEV-1/FVC ratio — the percentage of your total forced vital capacity exhaled in the first second; and DLCO (Diffusion Capacity of the Lung for Carbon Monoxide) — a measure of how well oxygen passes from the lungs into the blood.
The VA uses these values as percentages of the predicted normal value for someone of your age, height, and sex. A lower percentage indicates greater impairment. For example, an FEV-1 of 56-70% predicted typically warrants a 30% disability rating for restrictive lung disease, while FEV-1 of 40-55% predicted warrants 60%.
The VA must use post-bronchodilator results (after inhaler use) unless the pre-bronchodilator results are normal or the examiner determines post-bronchodilator testing is not appropriate. This is important because post-bronchodilator numbers are usually better, which could result in a lower rating. If the pre-bronchodilator results more accurately reflect your functional impairment, discuss this with your examiner.
During the PFT, give maximum effort on each attempt. The test requires you to inhale as deeply as possible and then exhale as hard and fast as you can. Inconsistent effort can invalidate the results. The technician will typically have you perform several attempts and use the best result.
Different diagnostic codes specify which PFT value to use. Some conditions are rated on FEV-1 alone, others on FEV-1/FVC ratio, and others on DLCO. The VA should apply whichever value produces the highest rating for the veteran.