Certain proteins found in blood serum have proven themselves as the new biomarkers in current efforts to definitively detect Alzheimer’s disease, according to researchers at University of Texas Southwestern Medical Center.
Together with results from a clinical exam, blood analysis would give a 94 percent accuracy rate in detecting suspected Alzheimer’s and an 84 percent accuracy rate in ruling it out in people without the disease, said the researchers.
“This research uses a novel technology that makes it possible to analyze several biomarkers in a single blood sample in a cost-effective way,” said Dr. Ramón Díaz-Arrastia, professor of neurology at UT Southwestern and senior author of the study.
Scientists have been working toward a simple blood test for Alzheimer’s for years, said Dr. Díaz-Arrastia, but no single substance, or biomarker, has proven successful. Such a test, he added, is comparable in principle to measuring blood cholesterol as a biomarker of cardiovascular disease.
Alzheimer’s disease, an incurable degenerative brain syndrome, currently affects about 5.3 million people over 65 in the U.S., according to the National Alzheimer’s Association. That number is predicted to reach 11 million or higher by 2050.
The disease is hard to diagnose, especially in the beginning stage when it resembles other cognitive problems. Tests for suspected Alzheimer’s are often expensive or invasive, and many patients are not able or willing to undergo them, the researchers said. Up until now, a sure diagnosis is only possible after the brain tissue of a deceased individual has been analyzed.
A simple blood test would be a convenient method for identifying Alzheimer’s that could given by health care workers almost anywhere. Furthermore, a definitive diagnosis would be very significant since treatments specifically targeting Alzheimer’s might not have any effect on other forms of neurodegenerative disease or cognitive decline, Dr. Díaz-Arrastia said.
In the current study, scientists, associated with the Texas Alzheimer’s Research Consortium, examined blood samples from 197 Texas patients who had suspected Alzheimer’s as well as 203 people without the disease.
More than 100 blood proteins were measured in the samples, and scientists used the results to develop a mathematical analysis that could calculate a person’s risk of having Alzheimer’s.
The analysis, together with information from a clinical exam, accurately detected Alzheimer’s 94 percent of the time, and correctly ruled out Alzheimer’s 84 percent of the time in people without the disease, Dr. Díaz-Arrastia said.
Neither the blood test nor a clinical exam by itself was as accurate as the blood test and clinical exam together, the researchers found.
“Having a diagnosis is an important step, but it’s not the end of the road unless you’ve got a treatment or a cure,” Dr. Díaz-Arrastia said.
The next step for the researchers involved is to determine whether or not the biomarker blood test can accurately detect Alzheimer’s in preserved blood serum from deceased patients who have been diagnosed definitively by an autopsy.
The study is published in the September issue of the Archives of Neurology.