Artist's rendering of a brain cell damaged by amyloid beta plaque in Alzheimer's disease

A new blood test that detects the presence of Alzheimer’s brain plaques on Thursday became the first to hit the commercial market on a wide scale, the developer says.

The PrecivityAD test involves a small blood sample taken in the clinical setting and then processed in a lab. It detects the presence of biomarkers for amyloid beta, a hallmark of the disease, and is consistent with the results of a diagnostic brain scan, according to C2N Diagnostics.

“While the test by itself cannot diagnose Alzheimer’s disease — which is a clinical diagnosis made by a healthcare provider — the test is an important new tool for physicians to aid in the evaluation process,” the St. Louis-based company said.

Following the patient’s blood draw, clinicians receive a lab report that provides an overall combined score, known as the Amyloid Probability Score. A low score indicates that the presence of amyloid brain plaques is unlikely, and a high score that plaques are likely present. An intermediate score is indeterminate and suggests that further diagnostic evaluation may be needed.

PrecivityAD is now available in 45 states, Washington, D.C., and Puerto Rico. C2N is working to obtain the certifications needed to offer test processing for California, Maryland, New York, Pennsylvania and Rhode Island.

A clinical game-changer

Image of Howard Fillit, M.D.
Howard Fillit, M.D.

An Alzheimer’s blood test is a breakthrough in several ways, said Howard Fillit, M.D., founding executive director and chief science officer of the Alzheimer’s Drug Discovery Foundation, which helped fund the developer’s research.

It’s a method that clinicians are familiar with, and provides objective, specific results that compliment cognitive testing “which is necessary, but often more variable and less precise,” he told McKnight’s.

A biomarker blood test also has advantages over current diagnostic methods, Fillit added. It is much less expensive than neuroimaging (which may require a radioactive drug injection) and less invasive than a spinal tap. 

Meanwhile, a widely available blood test may enable earlier diagnosis by making it easier to identify people with preclinical symptoms of Alzheimer’s. 

“This gives patients and their families the opportunity to receive prevention counseling and institute early care planning,” Fillit said.

PrecivityAD in early 2019 was designated a Breakthrough Device by the Food and Drug Administration in a program that speeds up development, assessment, and review of medical devices or device-led combination products that provide more effective treatment or diagnosis of life-threatening or irreversibly debilitating diseases or conditions.