Supplementary Figure 1. Levels of Aβ42, T- and P-Tau As Measured by ELISA Assay

Supplementary figure 1. Levels of Aβ42, t- and p-tau as measured by ELISA assay.

Supplementary figure 2. Boxplots showing biomarker values in neuropathological cases according to Braak stages and CERAD scores. First shows

Aβ42 (a), t-tau (b) and p-tau (c) values for the different CERAD scores. Second row shows Aβ42 (d), t-tau (e) and p-tau (f) values for the different

Braak stages in patients with AD pathology. Third row shows Aβ42 (g), t-tau (h) and p-tau (i) values for the different Braak stages in patients without AD pathology. Supplementary table 1. Agreement between clinical and neuropathological diagnosis. Clinical Diagnosis AD LPA Bv FTD CBS P SD FTD- P DLB MCI PPA

MND S

P AD 55 (+) 2 (+) 7 (-) 3 (-) 1 1 (-) 1 (±) 1 (±) Neuropatho- AD-Mixed 18 (+) 1 (-) 4 (-) 2(±) 1 (±) FTLD 3 (-) 1 (-) 12 (+) 4 (+) 3 1 (+) 1 (+) 1 1 (-) 1 (±) logical (+ diagnosis ) FTLD- 2 (±) 3 (+) 1 (+)

Mixed DLB 1 (±) 1 (-) 1(-) 4 (+) Agreement 96.0% 66.7% 65.2% 33.3% 7 33.0% 100.0% 1 80.0%

% Overall agreement was 81.4%. Boxes labeled as (+) indicate agreement and boxes labeled as (-) indicate wrong clinical diagnosis. Cases whose clinical diagnosis was concordant with the secondary neuropathological diagnoses are labeled as (±) and were not used for estimation of percent of agreement. Supplementary Table 2. Association between CERAD and Braak scores with CSF biomarkers.

Braak CERAD Assay p-value CSF p-value CSF p-value analyte sampling-death p-value analyte sampling-death interval interval

Aβ42 (all cases) Luminex . - <0.0001 0.24 T-tau in cases with 0.044 0.22 AD Luminex P-tau in cases with 0.097 0.25 AD Luminex T-tau in cases 0.78 0.64 without AD Luminex P-tau in cases 0.055 0.39 without AD Luminex

Aβ42 (all cases) ELISA 0.003 0.026 T-tau in cases with 0.013 0.020 AD ELISA P-tau in cases with 0.017 0.12 AD ELISA T-tau in cases ELISA 0.85 0.38 without AD P-tau in cases ELISA 0.39 0.21 without AD Ordinal logistic regression models for the biomarker values predicting the neuropathological score in an ordinal logistic regression. All models are adjusted by CSF sampling-death interval. Supplementary table 3. Statistically different biomarker measurements between FTLD, AD and control groups in the ELISA and Luminex assays using Nemenyi-Damico-Wolfe-Dunn pot-hoc test.

Aβ42 T-Tau P-Tau ELISA Luminex ELISA Luminex ELISA Luminex Cognitively normal controls <0.0001 <0.0001 <0.0001 <0.0001 <0.0001 0.002 vs. AD Cognitively normal controls 0.005 0.003 0.905 0.184 0.343 0.207 vs. FTLD AD vs. FTLD 0.0001 <0.0001 <0.0001 <0.0001 <0.0001 <0.0001

A non-parametric test (Kruskall-Wallis test) was used to compare CSF tau and Aβ measurements on both platforms (ELISA and Luminex) across the different neuropathological groups. P-values were corrected for multiple comparisons using Bonferroni correction and if significant the

Nemenyi-Damico-Wolfe-Dunn test was used as a post-hoc procedure [1, 2]. Supplementary table 4. Area under the curve and accuracy of the single analytes and ratios and the selected combination in the training- validation sample.

ELISA Luminex Assay AD vs. FTLD & Controls FTLD vs. controls AD vs. FTLD & Controls FTLD vs. controls AUC Accuracy AUC Accuracy AUC Accuracy AUC Accuracy Aβ 78.5% 65.5% 72.1% 69.5% 93.5% 86.4% 67.6% 63.2%

(65.4%- (51.4%- (55.1%- (52.9%- (88.3%- (77.0%- (49.6%- (46.0%-

91.7%) 77.8%) 89.1%) 82.4%) 98.8%) 93.0%) 85.7%) 78.2%) t-tau 81.8% 72.7% 51.0% 61.9% 78.8% 75.3% 54.3% 68.4%

(70.7%- (59.0%- (31.9%- (45.6%- (68.9%- (64.5%- (34.7%- (51.4%-

92.9%) 83.7%) 70.0%) 76.4%) 88.8%) 84.2%) 74.0%) 82.5%) p-tau 79.6% 65.5% 58.2% 59.5% 71.8% 67.9% 87.2% 89.5%

(67.5%- (51.4%- (39.5%- (43.3%- (60.7%- (56.6%- (72.5%- (75.2%-

91.7%) 77.8%) 76.9%) 74.4%) 82.9%) 77.9%) 100.0%) 97.1%) t-tau/Aβ 88.7% 87.5% 67.3% 61.9% 90.4% 85.2% 65.4% 68.4%

(79.8%- (74.8%- (49.5%- (45.6%- (83.5%- (75.6%- (47.3%- (51.4%-

97.7%) 95.3%) 85.2%) 76.4%) 97.4%) 92.1%) 83.4%) 82.5%) p-tau/Aβ 85.6% 87.5% 64.2% 59.5% 87.0% 77.8% 84.0% 79.0% (75.2%- (74.8%- (46.7%- (43.3%- (78.9%- (67.2%- (68.8%- (62.7%-

96.0%) 95.3%) 81.7%) 74.4%) 95.2%) 86.3%) 99.2%) 90.5%) Selected 93.0% 86.1% 72.1% 69.5% 93.7% 90.1% 90.7% 92.1% model (86.9%- (75.9%- (55.1%- (52.9%- (87.9%- (81.5%- (78.0%- (78.6%-

99.1%) 93.1%) 89.1%) 82.4%) 99.5%) 95.6%) 100.0%) 98.3%) The values in parentheses represent the 95% CI.

Supplementary table 5. Coefficients of the obtained logistic regression models obtained based on neuropathological and clinical diagnoses.

Assay Category 0 Category 1 Intercept Age T-Tau P-Tau Aβ42 ELISA AD FTLD & 0.10 -0.006 0.006

Controls ELISA FTLD Controls -1.98 0.005 ELISA AD FTLD 1.40 -0.014 0.007 Luminex AD FTLD & -6.41 -0.027 0.038

Controls Luminex FTLD Controls -7.88 -0.046 0.23 0.033 Luminex AD FTLD -6.20 -0.19 0.046 ELISA Clinical AD Clin. FTLD 3.34 -0.012 0.022 Luminex Clinical. AD Clin. FTLD -2.64 0.024 0.057 If not stated diagnoses are based on neuropathological diagnoses.

Supplementary table 6: Comparison of classification of neuropathological cases with a single neuropathological diagnosis based on clinical diagnosis and Luminex classification.

Clinical AD Clinical FTD Luminex AD 48 AD (npath. Dx) (±) 12 AD (npath. Dx) (+)

1 FTLD (npath. Dx) (-) Luminex FTD 1AD (npath. Dx) (-) 10 FTLD (npath. Dx) (±)

3 FTLD (npath. Dx) (+) (±): No difference in diagnostic accuracy between clinical diagnosis and Luminex classification. (+):Luminex classification improves diagnostic accuracy.

(-):Luminex classification worsens diagnostic accuracy. npath. Dx: neuropathological diagnosis.

References

1. Hollander M and Wolfe DA (1999) Nonparametric Statistical Methods, 2nd Edition. 1999, New York: John Wiley & Sons. 2. Hothorn T, Hornik K, van de Wiel MA and Zeileis A (2006) A Lego System for Conditional Inference. The American Statistician 60(3): 257- 263.