Table 5:

Standard investigations when patients with chronic obstructive pulmonary disease seek medical attention for suspected disease exacerbation

	Essential	Dependent on context or presentation
Inflammation and infection
Full blood count	X
C-reactive protein or procalcitonin	X
Airway microscopy and culture		X
Airway cytology (eosinophils)		X
Airway molecular testing for pathogens		X
Fractional exhaled nitric oxide		X
Hypoxia, hypercapnia, and metabolic status
pH of venous blood gas		X
Arterial oxygen saturation	X
General physiology
Breathing rate	X
Electrocardiography	X
Lung function		X
Imaging
Chest radiography, ultrasonography, or CT	X
Systemic measurements
D-dimer	X
Renal function		X
Troponin		X
B-type natriuretic peptide		X