A blood test to screen people for possible signs of Alzheimer’s disease and other forms of dementia has been a long-sought goal for scientists. Now, one may be on the horizon. Promising results have been see in multiple studies around the world researching the issue. Some experts are now estimating that a screening test could be as close as three years away.
Half a dozen research groups gave new results on various experimental tests at the Alzheimer’s Association International Conference this week. Two appeared especially promising. Both types of blood tests measured a specific type of protein in the blood. They both appeared to be successful in a large majority of the patients they were tested on.
The first was a blood test that measures abnormal versions of the protein that form the plaques in the brain that characterize Alzheimer’s. Japanese researchers tested the method on 201 people with Alzheimer’s, other types of dementia, mild impairment, or no symptoms. The results were measured against results from the top tests used now – three types of brain scans and a mental assessment exam. The test was accurate for 92 percent of people who had Alzheimer’s and correctly ruled out 85 percent who did not have it, for an overall accuracy of 88 percent.
The study of another experimental blood test that looked at a protein that’s a marker of nerve damage was conducted in 2,300 people with various neurological conditions, including Alzheimer’s, other dementias, Parkinson’s, depression, multiple sclerosis, Lou Gehrig’s disease. When the results were compared to those of healthy people, the blood test found protein levels that were significantly higher for eight conditions. Only 2 percent of healthy folks were found to be above the threshold the researchers set for raising concern.
It is estimated that roughly 50 million people worldwide have dementia. Alzheimer’s is the most common form. Doctors are hoping for a test to use during routine exams to gauge who needs more extensive testing. A blood test could be effective at getting patients into the right types of treatment sooner.