A past lung infection with tuberculosis bacteria that is no longer active but may have left scarring.
Because the rating depends on measurable residuals, pulmonary function test results are the most direct evidence. Spirometry showing FEV-1 and FEV-1/FVC values, as well as DLCO (SB) testing, maps directly to the percentage thresholds that separate each rating level. If exercise capacity is at issue, records of maximum oxygen consumption testing with a noted cardiac or respiratory limitation support the 60% and 100% levels.
For the highest rating level, medical records documenting cor pulmonale, right ventricular hypertrophy, pulmonary hypertension confirmed by echocardiogram or cardiac catheterization, episodes of acute respiratory failure, or a prescription for outpatient oxygen therapy all correspond to specific 100% criteria. Treatment records showing ongoing respiratory care and hospitalizations help establish the severity and chronicity of your condition. Statements from you or people who know you describing how breathing problems affect your ability to work or carry out daily activities can give context to what the test numbers reflect in practice.
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.
