Table 1.

Definitions of WHO chest radiograph findings (adapted from Cherian et al and Mahomed et al)^{5 7}

Finding		Definition
Quality	Interpretable	Image is sufficiently interpretable for determining the presence or absence of alveolar consolidation
	Uninterpretable	Image is insufficiently interpretable for determining the presence or absence of alveolar consolidation
Classification	Alveolar consolidation	Presence of a dense or fluffy opacity occupying a portion* or whole of a lobe or of the entire lung, which may or may not include air bronchograms and may or may not produce a silhouette sign†
	Other infiltrate	Linear or patchy densities not meeting alveolar consolidation criteria that may also be configured in a lacy pattern in one or both lungs, usually featuring peribronchial thickening or multiple areas of atelectasis
	Pleural effusion	Fluid in the lateral pleural space between the lung and chest wall, not including fluid in the horizontal or oblique fissures
Conclusion	PEP	Presence of alveolar consolidation or pleural effusion that is associated with any type of consolidation (alveolar or other infiltrate)
	Other infiltrate	Presence of other infiltrate not associated with a pleural effusion
	No PEP or other infiltrate	Absence of alveolar consolidation, other infiltrate or pleural effusion

*Defined as a consolidation that has its smallest diameter greater than or the same size as one posterior rib and its adjacent rib space at the same level as the consolidation.

†Defined as the loss of an anatomical border adjacent to any consolidation.

PEP, primary endpoint pneumonia.