Test	Potential diagnosis
Perform routinely
Pulse oximetry	Hypoxemia
Perform if hospitalized
Arterial blood gas measurement	Hypercarbia
	Hypoxemia
	Respiratory acidosis
Chest radiography	Alternate sources of dyspnea
Complete blood count	Anemia
	Leukocytosis
	Polycythemia
Electrocardiography	Cardiac arrhythmias
	Cardiac ischemia
Metabolic panel	Electrolyte disturbances
	Hypo- or hyperglycemia
	Metabolic acid-base changes
Consider performing, especially if patient is not responding to conventional exacerbation treatment
Brain natriuretic peptide measurement	CHF (one third of dyspnea in chronic lung disease may be attributable to CHF)
Cardiac enzyme measurement	Cardiac ischemia (myocardial infarction is underdiagnosed in patients with COPD)