Table 2:

Pretest and posttest probabilities of DCI based on clinical classification schemes^a

Clinical Classification Schemes	Pretest Probability (95% CI)	Posttest Probability
Clinical Classification Schemes	Pretest Probability (95% CI)	CTP-Positive (95% CI)	CTP-Negative (95% CI)
Hunt and Hess grades 1–2²¹	0.35 (0.25–0.45)	0.62 (0.52–0.72)	0.10 (0.04–0.16)
Hunt and Hess grades 3–5²¹	0.61 (0.53–0.70)	0.82 (0.74–0.90)	0.25 (0.16–0.34)
Glasgow Coma Scale ≥9²¹	0.45 (0.38–0.53)	0.72 (0.63–0.81)	0.15 (0.08–0.22)
Glasgow Coma Scale <9²¹	0.71 (0.57–0.86)	0.88 (0.82–0.95)	0.35 (0.26–0.45)
Modified Fisher grade 1²⁶	0.13 (0.0–0.29)	0.31 (0.22–0.40)	0.03 (0.0–0.06)
Modified Fisher grade 2, 3²⁶	0.20 (0.11–0.28)	0.44 (0.34–0.54)	0.05 (0.01–0.09)
Modified Fisher grade 4²⁶	0.36 (0.24–0.47)	0.66 (0.57–0.75)	0.11 (0.05–0.17)

↵a The pretest probabilities are based on literature review and the posttest probabilities are calculated from the CTP test characteristics derived from this study.