Diagnostic value of cerebrospinal fluid Aβ ratios in preclinical Alzheimer’s disease

Table 4 Diagnostic performance of different CSF analytes measured with the INNOTEST assay for Aβ42, ttau, and ptau at an optimal specificity and at a specificity fixed at 90 % or 95 %

	AUC	SE	95 % CI	Cutoff^a	Sensitivity (%)	Specificity (%)	Correctly classified^b (%)
Aβ42	0.935	0.0394	0.806–0.989	853	100	83.87	87
ttau	0.733	0.132	0.565–0.863	352	71.43	77.42	76
ptau	0.675	0.139	0.504–0.818	86	42.86	93.55	84
Aβ42/ttau	0.880	0.0878	0.734–0.963	2.258	85.71	90.32	89
Specificity of 90 %	Sensitivity (%)		95 % CI	Cutoff^a	Difference^c (%)	P value^d	Correctly classified^b (%)
Aβ42	85.71		11.54–100.00	798	7.90	0.25	89
ttau	57.14		14.29–100.00	465	10.53	0.125	82
ptau	42.96		0.00–85.71	87	5.26	0.5	79
Aβ42/ttau	85.71		28.57–100.00	2.263	0	1	89
Specificity of 95 %	Sensitivity (%)		95 % CI	Cutoff^a	Difference^c (%)	P value^d	Correctly classified^b (%)
Aβ42	42.86		4.05–100.00	672	21.05	0.008	87
ttau	14.29		0.00–85.71	566	23.69	0.004	82
ptau	28.57		0.00–71.43	94	2.63	1	82
Aβ42/ttau	71.43		8.71–100.00	2.093	7.90	0.25	92

Analyte concentrations are described as pg/ml or calculated as ratios between concentrations of two analytes
^aCutoff value corresponding to the highest Youden index
^bPercentage of positively classified cases based on the CSF cutoff value compared with amyloid PET classification
^cPercentage of subjects who were classified differently based on the cutoff values from fixed specificities compared with the cutoff values corresponding to the highest Youden index
^dSignificance for the “Difference”
Aβ amyloid beta, AUC area under the receiver operating characteristic curve, CI confidence interval, CSF cerebrospinal fluid, PET positron emission tomography, ptau ¹⁸¹phospho-tau, SE standard error, ttau total tau

ISSN: 1758-9193