Hi, Thanks for writing in to us. At first I would like to re assure you that two cysts measuring 10 mm in diameter are totally harmless and you need not worry for that. Coming to the PFTs, these are pulmonary function tests or lung function tests. Pulmonary function tests are a group of tests that measure how well the lungs take in and release air and how well they move gases such as oxygen from the atmosphere into the body s circulation. Spirometry measures airflow. By measuring how much air you exhale, and how quickly, spirometry can evaluate a broad range of lung diseases. In a spirometry test, while you are sitting, you breathe into a mouthpiece that is connected to an instrument called a spirometer. The spirometer records the amount and the rate of air that you breathe in and out over a period of time. For some of the test measurements, you can breathe normally and quietly. Other tests require forced inhalation or exhalation after a deep breath. Sometimes you will be asked to inhale the substance or a medicine to see how it changes your test results. Individuals with COPD often have abnormal PFT results which suggest airway blockage and air trapping. Similar changes can be seen in some other lung conditions, such as asthma. If the lung function testing includes a diffusing capacity (DLCO) test, a low value suggests emphysema. Hope this helps