Blood Test Predicts Alzheimer's Disease with Over 90% Accuracy

Alzheimer’s disease impacts one in five women and one in ten men over their lifetimes, yet diagnostic tools are still often cumbersome and not widely accessible in primary care settings. Although specialized memory clinics frequently use advanced diagnostic methods like PET scans and cerebrospinal fluid tests, there is a significant need for simpler, quicker diagnostic tools that can be used in primary care. Now, a commercially available blood test has demonstrated approximately 90% reliability in primary care settings, representing a major development for individuals seeking assistance for memory loss and potential Alzheimer’s.

The PrecivityAD2 test, developed by C2N Diagnostics (St. Louis, MO, USA), requires a single blood sample and uses high-resolution mass spectrometry to accurately measure proteins in the blood that indicate the likelihood of amyloid plaques in the brain, a pathological hallmark of Alzheimer's disease. This test utilizes a rigorously validated algorithm that combines plasma Aβ42/40 and p-tau217/np-tau217 (%p-tau217) ratios. It delivers clear positive or negative results, indicating a high or low probability of brain amyloid pathology. Research into this cutting-edge blood test began in 2019, with studies showing that the PrecivityAD2 test can detect Alzheimer's-related changes even before symptoms emerge and track disease progression. Earlier this year, results indicated that this blood test is as reliable as, and sometimes better than, cerebrospinal fluid tests for diagnosing the disease.

Image: The groundbreaking Alzheimer’s blood test has proven highly effective in primary healthcare (Photo courtesy of 123RF)

The latest study, conducted at Lund University (Lund, Sweden) and published in the renowned journal JAMA, is the first to evaluate the reliability of the PrecivityAD2 test in routine healthcare settings, including both primary and specialist healthcare. The study involved 1,213 individuals with mild memory symptoms, which may be an early indicator of Alzheimer’s. Of these participants, 515 were assessed in primary care and 698 in specialist memory clinics. Participants underwent the blood test and the results were later validated through cerebrospinal fluid tests that detect Alzheimer’s disease pathology. PrecivityAD2’s reliability for identifying Alzheimer’s disease was about 90%, which was then compared with the diagnostic accuracy of doctors in primary or specialist care before they had access to the results of the blood or cerebrospinal fluid tests. Accuracy rates for diagnosing Alzheimer’s disease were 61% among primary care doctors and 73% among specialists. The simplicity and accuracy of this blood test represent significant progress in diagnosing Alzheimer’s, providing a straightforward way to exclude the disease in primary care settings. This is vital since memory loss can also arise from other treatable conditions such as depression or chronic fatigue.

“The next steps include establishing clear clinical guidelines for the blood test’s use in healthcare,” said Professor Oskar Hansson from Lund University who co-led the study. “The test is already available in the USA and is likely to become available in many other countries soon. Initially, it will mainly be used in specialist memory clinics, and it may take approximately one to two years to implement guidelines and training in primary care.”

Related Links:
Lund University
C2N Diagnostics