Investigations

• creatine kinase ^c

Why?

A raised creatine kinase makes Legionella pneumonia more likely

Patient	Target Disorder and Reference Standard	Diagnostic Test	LR+ (95% CI)	Post-test Probability
possible Legionella infection c (pre-test probability: 12%)	Legionella pneumonia (microscopy or serology)	CK > 232 U/l	5.8 (1.5 to 22)	44%