<human>: I have just come home from a Spirometry test - I have been diagnosed in the past with Asthma and now they are telling me that I have decreased lung capacity ..... What might be the cause of that ?? .... I will be continuing on the next phase to see someone re Lung tests - but, in the meantime - what might they be looking for ??
<bot>: Welcome to Chat Doctor. Thank you for posting your question. I can understand your concern. In a spirometry test, one usually cannot comment on the Lung capacity. We usually measure a ratio between FEV1 (amount of air one can forcefully breathe out in the first minute) and FVC of FORCED VITAL CAPACITY (total amount of air one can forcefully breathe out)See, there are roughly two types of diseases :a) Restrictive like Interstitial Lung disease : Ratio is normal , overall lung capacity is decreased) Obstructive like asthma, COPD (chronic obstructive pulmonary disease).   Ratio is reduced , overall lung capacity is increased. Do not worry. Each of these can be kept in control with proper intervention. It would have better if I could see the reports. I would suggest you to consult a pulmonologist and clear all your doubts. He can guide you on the further workups and management plan. Hope this helps. Post any other question. We will be happy to help. Have a nice day. Regards.