Lung inflammation and scarring caused by medication that may lead to breathing difficulty.
Because the ratings turn almost entirely on specific lung function measurements, pulmonary function test results are the most direct evidence. Records showing your FVC as a percentage of the predicted value, or your DLCO (SB) as a percentage of the predicted value, correspond directly to each rating level. If your testing included a cardiopulmonary exercise test, the report showing maximum oxygen consumption in ml/kg/min and whether the limitation was cardiorespiratory also maps to the criteria.
Medical records documenting a diagnosis of cor pulmonale or pulmonary hypertension, or a prescription and records of use for outpatient oxygen therapy, can support a 100% rating on their own.
Treatment records, imaging such as CT scans showing fibrosis or inflammation, and notes from your pulmonologist can help establish the diagnosis and show how your condition has changed over time. Statements from you or people who know you describing how breathing difficulty affects your ability to work, walk, exercise, or carry out daily activities can give context to what the test numbers mean in your life.
Conditions that are often caused or made worse by this one. If you have any of these, they may be claimable as secondary service connection.
