(CNN) — In a first-of-its-kind study, researchers have developed a blood test for Alzheimer’s disease that predicts with astonishing accuracy whether a healthy person will develop the disease.
Though much work still needs to be done, it is hoped the test will someday be available in doctors’ offices, since the only methods for predicting Alzheimer’s right now, such as PET scans and spinal taps, are expensive, impractical, often unreliable and sometimes risky.
"This is a potential game-changer," said Dr. Howard Federoff, senior author of the report and a neurologist at Georgetown University Medical Center. "My level of enthusiasm is very high."
The study was published in Nature Medicine.
'We were surprised'
In the beginning, the researchers knew they wanted to find a blood test to detect Alzheimer’s but didn’t know what specifically to look for. Should they examine patients’ DNA? Their RNA? Or should they look for the byproducts of DNA and RNA, such as fats and proteins?
They decided to start with fats, since it was the easiest and least expensive. They drew blood from hundreds of healthy people over age 70 living near Rochester, New York, and Irvine, California. Five years later, 28 of the seniors had developed Alzheimer’s disease or the mild cognitive problems that usually precede it.
Scouring more than 100 fats, or lipids, for what might set this group apart, they found that these 28 seniors had low levels of 10 particular lipids, compared with healthy seniors.
To confirm their findings, the researchers then looked at the blood of 54 other patients who had Alzheimer’s or mild cognitive impairment. This group also had low levels of the lipids.
Overall, the blood test predicted who would get Alzheimer’s or mild cognitive impairment with over 90% accuracy.
"We were surprised," said Mark Mapstone, a neuropsychologist at the University of Rochester Medical Center and lead author of the study. "But it turns out that it appears we were looking in the right place."