Investigations

Why?

• A pneumococcal PCR test is the most sensitive method of detecting pneumococcal pneumonia (sensitivity: 55%). ^c

 A rpositive pneumococcal PCR diagnoses pneumococcal pneumonia

Patient	Target Disorder and Reference Standard	Diagnostic Test	LR+ (95% CI)	Post-test Probability	LR- (95% CI)	Post-test Probability
community-acquired pneumonia c (pre-test probability: 35%)	pneumococcal pneumonia (culture or serology)	pneumococcal PCR	infinity (5.8 to infinity)	100%	0.45 (0.32 to 0.63)	20%