Table 7.

Expectorate and potential diagnostic category.

Characteristics of
the expectorated sputum	Diagnostic category
Absent	No specific indication
Clear	Airway aspiration
	Upper airway associations
	Other specific diseases
	Non-infective airway inflammatory process
Purulent	Airway infection
	Airway aspiration
	Chronic suppurative airway disease
	Airway anomaly
Haematic	Airway infection
(haemoptysis)	Bronchiectasis
	Arterio-venous malformation
	Other specific diseases (e.g., hereditary
	haemorrhagic telangiectasia)
Casts	Other specific diseases (plastic bronchitis)