Evidence-based On-call

Community-acquired pneumonia

Clinical features

Rank your patient for risk of a pulmonary infiltrate on chest X-ray. Score one point for ^a

A high score makes pneumonia more likely

Why?

Clinicians are not very good at diagnosing or excluding pneumonia.

Patient	Target Disorder and Reference Standard	Diagnostic Test	LR+ (95% CI)	Post-test Probability	LR- (95% CI)	Post-test Probability
suspected pneumonia ^a (pre-test probability: 5%)	pneumonia (chest X-ray)	clinician's prediction	2.0 (1.5 to 2.4)	10%	0.25 (0.09 to 0.61)	1%

This clinical prediction rule can help rank patients for risk of pneumonia

Patient	Target Disorder and Reference Standard	Diagnostic Test	LR+ (95% CI)	Post-test Probability
suspected pneumonia ^a (pre-test probability: 15%)	pneumonia (pulmonary infiltrate on chest X-ray)	score: 5	17 (6.5 to 47)	75%
		4	7.2 (4.6 to 11)	55%
		3	1.6 (1.2 to 2.2)	22%
		2	0.70 (0.50 to 0.99)	11%
		1	0.20 (0.11 to 0.36)	3%
		0	0.12 (0.017 to 0.87)	2%