Alzheimer's Blood Test Found to Be Nearly As Accurate As Other Screening Methods
Michelle Milliken
Current methods to diagnose Alzheimer's can involve costly brain scans or invasive spinal fluid tests. Many people would prefer a less invasive, more affordable method, and new research says we could soon be there.
Researchers at Washington University School of Medicine have been testing the effectiveness of an Alzheimer's blood test they developed. In work recently published in the journal Neurology, they say when coupled with risk factors, their blood test was around 90% accurate in detecting early signs of the disease. Not only could this make things easier during the diagnosis phase, it may also help with early intervention.
Dr. Randall Bateman, senior author and professor of neurology, explains, "A blood test for Alzheimer’s provides a huge boost for Alzheimer’s research and diagnosis, drastically cutting the time and cost of identifying patients for clinical trials and spurring the development of new treatment options. As new drugs become available, a blood test could determine who might benefit from treatment, including those at very early stages of the disease."
The team's blood test - known commercially as Precivity AD - assesses the presence of amyloid plaque in the brain based on the ratio of blood levels of amyloid beta proteins Aβ42 and Aβ40. To conduct the study, they used this test with plasma samples from 465 patients in the United States, Sweden, and Australia. The researchers determined that when combined with the genetic variant APOE4, which is associated with Alzheimer's, the test was 88% accurate when compared to brain imaging and 93% compared to the spinal fluid test. This was true even with patients who were not showing any signs of cognitive decline.
Dr Bateman says, "These results suggest the test can be useful in identifying non-impaired patients who may be at risk for future dementia, offering them the opportunity to get enrolled in clinical trials when early intervention has the potential to do the most good. A negative test result also could help doctors rule out Alzheimer’s in patients whose impairments may be related to some other health issue, disease or medication."
In addition to these benefits, the team notes there's another important upside: the cost. They say that PET brain scans can run between $5,000 and $8,000 each, while tests to detect amyloid-beta and tau protein levels in spinal fluid can cost around $1,000 and involve a spinal tap. The team says a $500 test would allow a more affordable option. It should also allow patients to enroll in clinical trials sooner because the process would take less than six months.
The researchers noted that there are some limitations to the study, including that the sample was not very diverse. Currently, Precivity AD is also not yet covered by most insurance providers.
