Investigations

• creatinine kinase ^a

Why?

A raised CK makes a seizure much more likely

Patient	Target Disorder and Reference Standard	Diagnostic Test	LR+ (95% CI)	Post-test Probability	LR- (95% CI)	Post-test Probability
transient loss of consciousness a (pre-test probability: 44%)	tonic-clonic seizure (chart review)	CK ≥188 U/l	23 (3.2 to 170)	95%	0.58 (0.45 to 0.76)	31%