Body system: Respiratory SystemRegulation: 38 CFR § 4.97
Diffuse interstitial fibrosis is scarring throughout your lung tissue that makes it hard to breathe and get oxygen into your blood. The VA rates this condition from 0% to 100% based on specific lung function tests that measure how much air you can breathe in and how well your lungs transfer oxygen. Higher ratings go to veterans with worse lung function, need for oxygen therapy, or heart problems caused by the lung disease.
Rating levels
- 100% — You qualify for this rating if your lung function tests show your breathing capacity is severely reduced - specifically if you can only breathe out less than half the air volume expected for someone your age and size, or if your lungs can only transfer less than 40% of the expected amount of oxygen into your blood. You also qualify if exercise testing shows your body can only use a very small amount of oxygen during activity (less than 15 ml per kilogram of body weight per minute), or if the lung scarring has caused your heart to work too hard and become enlarged or caused high blood pressure in your lungs, or if you need to use supplemental oxygen at home or when out and about.
- 60% — You qualify for this rating if your lung function tests show your breathing capacity is reduced to 50-64% of what's expected for someone your age and size (measured by FVC - forced vital capacity), or if your lungs can only transfer 40-55% of the expected amount of oxygen into your blood (measured by DLCO), or if exercise testing shows your body can only use 15-20 ml of oxygen per kilogram of body weight per minute due to heart and lung limitations. These test results indicate significant lung scarring that substantially limits your breathing and physical activity.
- 30% — Your lung function tests show moderate impairment, with your Forced Vital Capacity (the total amount of air you can blow out after taking the deepest breath possible) measuring between 65-74% of what's expected for someone your age and size. Alternatively, this rating applies if your DLCO test (which measures how well oxygen moves from your lungs into your bloodstream) shows 56-65% of predicted normal values.
- 10% — Your lung function tests show mild impairment where your lungs can hold 75-80% of the air volume expected for someone your age and size (FVC test), or your lungs can only transfer 66-80% of the expected amount of oxygen from your lungs into your bloodstream (DLCO test). This represents early-stage lung scarring that causes some reduction in your breathing capacity but doesn't significantly limit your daily activities.