Fig. 1

The levels of QPLEX™ biomarkers and their correlation to cerebral amyloid deposition. a Correlation between IH-ELISA and QPLEX™ biomarkers and inter- or intra-CV. Significant outliers were excluded by the Grubb’s test method. b Classification of participants. Participants were divided into two groups (cerebral amyloid deposition; − or + means PiB− vs. PiB+) or three groups (depending on their cognitive status; CN normal, MCI mild cognitive impaired, Dementia). Comparison analyses for PiB− vs. PiB+ were conducted. c The levels of QPLEX™ biomarkers. *p <  0.05, **p <  0.01, independent t test; ^#p <  0.10, ^###p <  0.001, ^#####p <  0.0001, ANCOVA test with the correction of age, sex, ApoE, and/or MMSE score. d Correlation between cerebral amyloid deposition and QPLEX™ biomarkers. e Inter-correlations between the markers (Pearson’s correlation coefficient, p values, and variance inflation factor)