Spirometry results essentially normal spirometry. hyperinflation questionable the single breath diffusing capacity is moderately impaired. copd?

Possible: A reduced DLCO/Va points to damage or scarring in the lung tissue and emphysema (especially if you have been a smoker) or other interstitial lung diseases may be the cause. The normal lung function however is not compatible with COPD but then I don't understand what you meant by hyperinflation in the presence of normal lung function test. See a pulmonologist.