Body system: Respiratory SystemRegulation: 38 CFR § 4.97
Hypersensitivity pneumonitis (extrinsic allergic alveolitis) is an immune-mediated interstitial lung disease caused by repeated inhalation of organic antigens (farmer's lung, bird-fancier's lung, etc.). The VA rates this condition under the General Rating Formula for Interstitial Lung Disease (38 CFR § 4.97) from 10% to 100% based on pulmonary function testing: FVC (forced vital capacity), DLCO (diffusion capacity for carbon monoxide), maximum exercise capacity, and the presence of cor pulmonale, pulmonary hypertension, or required outpatient oxygen therapy.
Rating levels
- 100% — You qualify for 100% if pulmonary function testing shows FVC less than 50% predicted, OR DLCO (single-breath method) less than 40% predicted, OR maximum exercise capacity less than 15 ml/kg/min oxygen consumption with cardiorespiratory limitation, OR cor pulmonale (right-heart strain from chronic lung disease) or pulmonary hypertension is present, OR you require outpatient oxygen therapy. Any one of these findings is sufficient for the 100% rating.
- 60% — You qualify for 60% if pulmonary function testing shows FVC of 50% to 64% predicted, OR DLCO (single-breath method) of 40% to 55% predicted, OR maximum exercise capacity of 15 to 20 ml/kg/min oxygen consumption with cardiorespiratory limitation. Any one of these findings is sufficient.
- 30% — You qualify for 30% if pulmonary function testing shows FVC of 65% to 74% predicted, OR DLCO (single-breath method) of 56% to 65% predicted. Either finding is sufficient.
- 10% — You qualify for 10% if pulmonary function testing shows FVC of 75% to 80% predicted, OR DLCO (single-breath method) of 66% to 80% predicted. This represents mild impairment, either finding is sufficient.