Neurologists diagnose cognitive impairment through clinical exams of memory and thinking skills. To determine if Alzheimer’s disease is the cause, specific brain changes characteristic of Alzheimer’s must be identified, typically via brain scans or spinal taps.
Identifying individuals whose cognitive symptoms are due to Alzheimer’s is crucial, especially now that new therapies are available that could alter the disease’s progression.
To make diagnosis more accessible, several companies have started selling Alzheimer’s blood tests to consumers, with at least five companies offering these tests for clinical use. However, doctors have struggled to determine which tests are most accurate, as there has been no direct comparison using the same population, methods, and criteria until now.
Suzanne Schindler, MD, Ph.D., and her team at Washington University School of Medicine in St. Louis conducted a comparative analysis of six commercial blood tests to evaluate their accuracy in detecting Alzheimer’s disease, particularly the presence of amyloid plaques in the brain.
The analysis revealed that some tests are accurate enough to replace spinal taps and brain scans in many patients. These findings were presented at the Alzheimer’s Association International Conference in Philadelphia.
The study found that some blood tests are reliable while others are not, providing crucial information for doctors on which tests to use for an accurate diagnosis. Confirming that cognitive impairment is due to Alzheimer’s early is vital for ensuring access to new therapies.
Recently, the FDA approved two drugs that slow the disease’s progression, which target amyloid, requiring confirmation of amyloid buildup in the brain before prescription.
The team evaluated six blood tests from different companies to detect Alzheimer’s-related proteins in the blood.
They found that the biomarker p-tau217, measured by four of the tests, was exceptionally accurate in identifying Alzheimer’s signs. P-tau217 alone predicted levels of amyloid and tau in the brain, brain volumes, and cognitive symptoms more accurately than any other biomarker.
The top-performing tests were C2N Diagnostics’ PrecivityAD2 and Fujirebio’s Lumipulse. A recent paper in Nature Reviews Neurology set standards for blood tests, which the p-tau217 tests met, but others did not.
