Lung function tests are the base of diagnosis of obstructive pulmonary diseases. In elderly, development of these tests is very difficult, because there are contraindications and difficulties in cooperation during examination. In old age often coincidence of asthma and COPD occurs, moreover in these two diseases comorbidity, and in COPD
– low grade systemic inflammation is observed. All these separate phenomena have essential influence on therapeutic algorithms in asthma and COPD.