Blood Test May Predict Alzheimer's Risk
A recent study led by researchers at Washington University School of Medicine in St. Louis suggests amyloid beta markers in the blood may help identify people at increased risk for Alzheimer’s disease decades before symptoms—memory loss and confusion, for example—develop.
In people with Alzheimer’s, plaques made of a sticky protein called amyloid beta collect in the brain and contribute to the disease and its progression. At this time, the only tests available to detect amyloid beta plaques in the brain are PET scan, which is expensive and not widely available, and spinal tap, which is an invasive medical procedure.
Previous research suggested total levels of amyloid beta in the blood don’t correlate with levels in the brain. For this study, researchers focused on three subtypes—amyloid beta 38, amyloid beta 40, and amyloid beta 42. They studied 41 people over the age of 60, 23 of whom had signs of cognitive impairment and amyloid plaques in the brain detected by PET scan or amyloid alterations in the cerebrospinal fluid detected by spinal tap. According to researchers, the study accurately classified people as amyloid-positive or -negative in 89 percent of cases.