Table 2.

Serum Tau Cutoffs, Sensitivity, and Specificity

Time	Cutoff design	Cutoff, ng/l	Sensitivity	95% CI	Specificity	95% CI
24 h	Youden	6.1	0.68	0.63–0.73	0.79	0.75–0.84
	FPR = 0%	874.5	0.04	0.02–0.06	1.00	0.99–1.00
	FPR = 1%	82.6	0.17	0.13–0.21	0.99	0.98–1.00
	FPR = 2%	39.1	0.29	0.23–0.33	0.98	0.96–0.99
	FPR = 3%	24.7	0.35	0.30–0.40	0.97	0.95–0.99
	FPR = 4%	22.9	0.36	0.30–0.40	0.96	0.94–0.98
	FPR = 5%	21.5	0.37	0.31–0.41	0.95	0.92–0.97
48 h	Youden	6.9	0.77	0.72–0.81	0.91	0.88–0.94
	FPR = 0%	148.8	0.33	0.28–0.38	1.00	0.99–1.00
	FPR = 1%	32.0	0.54	0.49–0.60	0.99	0.98–1.00
	FPR = 2%	18.9	0.61	0.56–0.67	0.98	0.96–0.99
	FPR = 3%	13.3	0.66	0.61–0.72	0.97	0.95–0.99
	FPR = 4%	11.6	0.68	0.63–0.73	0.96	0.94–0.98
	FPR = 5%	10.3	0.69	0.65–0.75	0.95	0.93–0.97
72 h	Youden	4.4	0.78	0.73–0.83	0.9	0.87–0.93
	FPR = 0%	72.7	0.42	0.36–0.48	1.00	0.99–1.00
	FPR = 1%	13.4	0.63	0.57–0.69	0.99	0.97–1.00
	FPR = 2%	11.2	0.66	0.6–0.710	0.98	0.96–0.99
	FPR = 3%	10.3	0.67	0.62–0.73	0.97	0.95–0.98
	FPR = 4%	8.6	0.69	0.64–0.75	0.96	0.94–0.98
	FPR = 5%	7.9	0.71	0.65–0.77	0.95	0.92–0.97

Test sensitivity and specificity for serum tau (measured at 24 hours, 48 hours, or 72 hours after cardiac arrest) to separate poor outcome (CPC 3–5) from good outcome (CPC 1–2) at 180 days. Cutoffs were designed by the Youden index (which maximizes the combination of sensitivity and specificity), or at tau concentrations that resulted in FPR = 0–5%; 95% CIs for sensitivity and specificity were generated by a bootstrap procedure (n = 2,000 iterations).

CI = confidence interval; CPC = Cerebral Performance Categories; FPR = false positive rate.