Chronic<unk><unk><unk>  has irreversible airflow limitation specially during forced expiration. This is due to the destruction of lung tissue and increase in resistance to flow in the conducting airways. Thus, it doesn't show an improvement in FEV1 post bronchodilator administration (unlike asthma). This characteristic feature is used as an diagnostic criteria for COPD, i.e. a COPD is diagnosed by spirometry if FEV1/FVC < 70% for a matched control. Arterial blood gas may show hypoxemia with or without hypercapnia depending on the<unk>  severity. pH may be normal due to renal compensation. A pH less than 7.3 usually indicate severe respiratory compromise. A blood sample taken from an artery, i.e. Arterial Blood Gas (ABG), can be tested for blood gas levels which may show low oxygen (hypoxaemia) and/or high carbon dioxide (respiratory acidosis if pH is also decreased). A blood sample taken from a vein may show a high blood count (reactive polycythemia), a reaction to long-term hypoxemia.
Chronic obstructive pulmonary disease laboratory findings
Chronic bronchitis laboratory findings
Asthma laboratory findings
Alpha 1-antitrypsin deficiency laboratory findings
Pulmonary embolism laboratory findings
Bronchiectasis laboratory findings
Idiopathic pulmonary fibrosis physical examination
Respiratory failure laboratory findings