Clinical Validation and Real-World Impact of PrecivityAD2 Test for Alzheimer Diagnosis: Joel B. Braunstein, MD

WATCH TIME: 7 minutes

“With the PrecivityAD2 test, clinicians’ diagnostic confidence in Alzheimer disease rose from around 50-60% to over 90%, guiding treatment decisions and reducing unnecessary testing.”

The PrecivityAD2 blood test by C2N Diagnostics is a multianalyte assay designed to aid in the diagnosis of Alzheimer disease (AD) for patients 55 and older with symptoms of mild cognitive impairment (MCI) or dementia. Using high-resolution Liquid chromatography–tandem mass spectrometry (LC-MS/MS) technology, the test quantifies amyloid-ß (Aß)42 and Aβ40 isoforms and phosphorylated/non-phosphorylated tau217 peptides. These measurements are combined into the Amyloid Probability Score 2 (APS2), a numerical score from 0 to 100, with scores of 48 or above indicating positive brain amyloid plaques associated with AD pathology.

Validated in both the PARIS (IDEAS sub-study; NCT02420756) and 11 MissionAD studies (NCT02956486 and NCT03036280), the PrecivityAD2 test showed strong diagnostic performance, achieving an area under the curve (AUC) of 0.94 and an accuracy of 88% when amyloid PET served as the reference standard. In a separate, large-scale study (NCT06122415 and NCT06120361) of over 1200 patients in Sweden, the test maintained a diagnostic accuracy of 90% with high concordance to cerebrospinal fluid analysis (AUC, 0.96-0.97). Performance remained consistent across primary and secondary care settings and was unaffected by common comorbidities like cardiovascular disease, chronic kidney disease, and diabetes.

Recently, Joel B. Braunstein, MD, CEO at C2N Diagnostics, participated as a speaker in a roundtable focused on the plasma P-tau217 assays such as the PrecivityAD2 test at 2024 Clinical Trials on Alzheimer’s Disease (CTAD) conference, held October 29 to November 1, in Madrid, Spain. At the conference, Braunstein sat down with NeurologyLive^® to further discuss how the PrecivityAD2 blood test specifically enhanced diagnostic accuracy for AD based on findings from previous research. He also spoke about the impact of the PrecivityAD2 blood test had on clinicians’ decision-making and patient treatment plans. Furthermore, Braunstein talked more about how APS2 is calculated, and its role in differentiating AD pathology for studies.

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REFERENCES
1. Suárez-Calvet M, Braunstein JB, Beck R, et al. Plasma P-Tau217 Assays In Clinical Practice: Current Uses And Future Considerations For Diagnosing Alzheimer’s Disease. Presented at: 2024 CTAD; October 29-November 1; Madrid, Spain. LBRT1.