Table 3.

ROC analysis of plasma p-tau 217 for identifying abnormal CSF Aβ42/Aβ40 status

Plasma p-tau217	AUC (95% CI)	Sensitivity %	Specificity %	Cut-off	Youden’s Index
Cond 1: thaw at RT, NC	0.845 (0.769, 0.921)	88	72	0.282	.600
Cond 2: thaw at RT, C	0.872 (0.799, 0.945)	80	90	0.247	.700
Cond 3: thaw on ice, NC	0.884 (0.818, 0.951)	86	82	0.252	.680
Cond 4: thaw on ice, C	0.883 (0.813, 0.953)	76	92	0.256	.680

Abbreviations: Aβ⁺ Amyloid-β positive, Aβ⁻ Amyloid-β negative, AUC Area under the curve, CI Confidence interval, CSF Cerebrospinal fluid, C Centrifugation, Cond Condition, NC Non-centrifugation, ROC Receiver operating characteristic, RT Room temperature