Table 4. Receiver Operating Curve (ROC) Analysis for Abnormal Aβ-PET in the Alzheimer Disease Neuroimaging Initiativea.
Plasma assay | Aβ-PET, AUC (95% CI)b |
---|---|
Aβ+, No. | 59 |
Aβ−, No. | 63 |
Aβ42/40 IP-MS-WashU | 0.845 (0.772-0.917) |
Composite IP-MS-Shim | 0.821 (0.747-0.895) |
Aβ42/40 IA-Elc | 0.740 (0.651-0.829)c |
Aβ42/40 IA-N4PE | 0.685 (0.590-0.781)d |
Aβ42/40 IP-MS-UGOT | 0.662 (0.565-0.758)e |
Aβ42/40 IA-Quan | 0.634 (0.534-0.734)e |
Abbreviations: Aβ, amyloid-β; AUC, area under the curve; IA-Elc, Elecsys immunoassay from Roche Diagnostics; IA-N4PE, N4PE Simoa immunoassay from Quanterix; IA-Quan, Simoa immunoassay from Quanterix; IP-MS-Shim, immunoprecipitation coupled mass spectrometry method developed by Shimadzu; IP-MS-UGOT, immunoprecipitation-coupled mass spectrometry method developed at the University of Gothenburg; IP-MS-WashU, immunoprecipitation-coupled mass spectrometry method developed at Washington University; ROC, receiver operating characteristic; PET, positron emission tomography.
In ADNI, CSF Aβ42 and Aβ40 measures at the time of plasma collection were only available in a small group of participants, and therefore we used Aβ PET as the outcome.
AUCs of 2 ROC curves were compared with DeLong test. Aβ-PET data was binarized using a previously described threshold of 1.11. 14,15
P < .05, compared with IP-MS-WashU Aβ42/40.
P < .01, compared with IP-MS-WashU Aβ42/40.
P < .001, compared with Aβ42/40IP-MS-WashU.