An innovative blood test for Alzheimer’s disease, developed using technology invented at Washington University School of Medicine, has been cleared for marketing by the U.S. Food and Drug Administration.
The test, known as PrecivityAD2, is a blood-based diagnostic developed and validated by C2N Diagnostics, a WashU startup company. PrecivityAD2 helps identify the presence of amyloid plaques in the brain associated with Alzheimer’s disease in certain patients.
Unlike some other FDA-cleared blood tests that use immunoassay methods to analyze biomarkers associated with Alzheimer’s, PrecivityAD2 uses high-resolution mass spectrometry to provide quantitative measurements of the biomarkers.
“The FDA clearance of C2N’s blood test is a significant advancement in Alzheimer’s diagnostics and a testament to the culture of innovation at WashU Medicine,” said Doug E. Frantz, vice chancellor for innovation and commercialization at WashU.
The technology underlying the test was initially developed by a WashU team co-led by Dr. Randall J. Bateman and Dr. David M. Holtzman, both professors of neurology.
C2N Diagnostics was co-founded by Bateman, Holtzman and others in 2007. The company acquired exclusive commercial licensing rights to patented technologies developed in their laboratories and refined the tests for clinical use.
“The PrecivityAD2 test provides an accurate and reliable way to detect the presence of brain amyloid plaques associated with Alzheimer’s disease pathology based on a single blood draw,” Bateman told WashU’s The Source.
“With FDA clearance, this innovation can reach more patients, increasing early and accurate diagnoses for people who are seeking causes of cognitive symptoms such as memory loss. With faster diagnosis, patients can receive earlier treatment, when treatments are most effective.”
Black Americans are about twice as likely as older White Americans to develop Alzheimer’s disease and related dementias, making advances in diagnosis particularly important.
Approximately 21.3% of Black Americans ages 70 and older live with Alzheimer’s or other dementias. Contributing factors to the elevated risk include higher rates of cardiovascular disease, hypertension, type 2 diabetes and obesity.
Despite those higher risks, Black Americans are often diagnosed later in the disease’s progression and are less likely than White Americans to receive a timely, formal diagnosis.
Because diagnosing Alzheimer’s has often required expensive PET scans or invasive spinal taps, a validated blood test could make diagnosis easier and less invasive. However, some researchers remain cautious about whether all Alzheimer’s blood tests perform equally well across racial groups.
A 2022 Washington University study co-authored by researchers including Dr. Thomas K. Karikari, Dr. Suzanne Schindler and Bateman evaluated how Alzheimer’s blood tests performed among Black and White patients.
The study found that three of four blood-based biomarker measures performed differently across racial groups, raising concerns about the potential for inaccurate diagnoses.
The exception was PrecivityAD, a test using mass-spectrometry technology developed by Bateman’s team, which accurately classified patients across racial groups in the study.
PrecivityAD2 builds on that technology, measuring specific amyloid-beta ratios and another Alzheimer’s-related biomarker using high-resolution mass spectrometry. Some biomarkers used in Alzheimer’s blood tests can be affected by chronic conditions such as high blood pressure and diabetes, potentially complicating diagnosis.
Karikari and other researchers have emphasized the importance of validating diagnostic tests in diverse populations. Blood tests that have not been rigorously evaluated across racial groups could increase the risk of misdiagnosis or inappropriate medical treatment, particularly for Black patients.
They have called for greater Black participation in clinical studies to ensure that new Alzheimer’s blood tests are accurate and effective across racial groups.
Sylvester Brown Jr. is the Deaconess Foundation Community Advocacy Fellow.