Researchers have determined that healthcare providers increased their ability to make Alzheimer’s disease (AD) probability judgments on their patients when they used the PrecivityAD2™ blood biomarker (BBM) tests from C2N Diagnostics, LLC, which aid them in the detection of amyloid plaques in the brain, a pathological hallmark of AD. This change in clinician-reported probability of AD is also associated with meaningful improvements in downstream clinical care, including changes in plans for AD medications as well as additional brain amyloid testing.
This research, Clinical Utility of an Alzheimer’s Disease Blood Test Among Cognitively Impaired Patients: Results from the Quality Improvement PrecivityAD2 (QUIP II) Clinician Survey Study, was published in the peer-reviewed Diagnostics journal. The research found:
- With the PrecivityAD2 blood test, clinicians’ diagnostic confidence in AD rose from approximately 50-60% to over 90% among patients with a positive Amyloid Probability Score 2 (APS2) result, guiding management decisions.
- Patients with a positive APS2 result (which would be consistent with an AD diagnosis) had a 35% increase in AD medication prescribing as well as increased use of disease-modifying therapy lecanemab.
- Patients with a negative APS2 (which would be inconsistent with an AD diagnosis) had an over 70% reduction in AD medication prescribing and additional brain amyloid testing.
- Clinicians prescribed the blood test in high accordance with its intended use criteria.
The QUIP II study (NCT06025877) involved eight academic and community-based practice sites, and 12 memory specialists who treated a total of 203 patients presenting with AD symptoms or other causes of cognitive decline. It included a final analysis cohort of 28% patients that were identified by the clinician as typically under-represented Black, Hispanic and Asian minorities; they had a median age of 74 and over half (53%) were female.
The memory specialists received education and training on the intended use of this BBM test as well as the APS2 result, which combines the plasma Aβ42/Aβ40 ratio and the ptau217/np-tau217 ratio (%p-tau217) measurements in a statistical algorithm to yield the score that informs on the likelihood of brain amyloid plaques. Each clinician then completed a survey that was built within a HIPAA (Health Insurance Portability and Accountability Act) compliant survey system. The survey collected clinician feedback concerning pre- and post-BBM test diagnostic certainty, as well as pre- and post-BBM test patient management plans, including medication prescribing and additional brain amyloid evaluation.
Dr. Robert M. Carlile, one of the study investigators based at Palmetto Primary Care Physicians in Summerville, S.C., says, “Patients and families have greatly benefited from healthcare providers having access to C2N’s PrecivityAD2 blood test to help diagnose Alzheimer’s disease. The test was straightforward to incorporate into my clinical practice. The overall outcome has been clinically meaningful changes in decision-making around AD diagnostic certainty, drug therapy management and additional brain amyloid evaluation among patients evaluated for cognitive impairment. This all increases our ability to develop diagnostic certainty and impact clinical management in patients.”
Dr. Joel Braunstein, CEO of C2N Diagnostics, says, “This research increases the growing body of evidence that demonstrates high clinical utility with blood biomarkers, which is bringing important advancements to the field. Too often, patients face a complex and delayed diagnostic journey when dealing with new cognitive concerns. High-performance testing with our PrecivityAD2 blood test has the potential to provide clarity and shorten that diagnostic journey, while significantly elevating healthcare quality.”
The research builds on a large clinical study published in 2024 in the Journal of the American Medical Association (JAMA) that examined the ability of the PrecivityAD2 blood test’s APS2 result to improve the diagnostic accuracy of AD in primary care settings, where most patients with cognitive concerns turn to for initial answers about their memory loss. The study found similar robustness for the APS2 result in patients who saw memory care specialists. The APS2 delivered a highly statistically significant accuracy of over 90% at a pre-defined, single binary cutoff compared to cerebrospinal fluid (CSF) analysis or amyloid PET analysis.
The QUIP II study reinforces the findings of the original QUIP I study, which evaluated the PrecivityAD® blood test with 43 memory care specialists caring for 366 patients; QUIP I was one of the first clinical utility studies that examined the real-world impact of a blood biomarker test for aiding in AD diagnosis and management. In that study, the PrecivityAD test provided clinically informative results in approximately 85% of cases and enabled clinicians to more confidently rule in or rule out a diagnosis of clinical AD.
Both the PrecivityAD2 and PrecivityAD blood tests are accessible by order of a healthcare provider. They are available in 49 states in the U.S., excluding New York (where certification is pending), as well as the District of Columbia and Puerto Rico.
