Clinical features

• a cough ^a
• fever ^a
• respiratory rate > 30 per minute ^a
• tachycardia ^a

Why?

No cough and normal vital signs make pneumonia less likely

Patient a	Target Disorder and Reference Standard	Diagnostic Test	LR+ (95% CI)	Post-test Probability	LR- (95% CI)	Post-test Probability
suspected pneumonia (pre-test probability: 5%)	pneumonia (chest X-ray)	cough	1.8	9%	0.31	2%
		fever	2.1 (1.4 to 2.9)	10%	0.59	3%
		respiratory rate > 30/minute	2.6	12%	0.80	4%
		any of respiratory rate > 30, heart rate > 100, temperature > 37.8 C	1.2	6%	0.18 (0.07 to 0.46)	0.9%