The as-yet-unnamed test would be used initially with other diagnostic tests, such as brain scans, to provide a highly reliable result, says Cris McReynolds, president of Satoris. "It will be an important piece of information used with other information to make an accurate diagnosis."
McReynolds says he hopes a test for the general public will become available one or two years after researchers begin their work with it.
Another test, called NuroPro, is under development by Power3 Medical Products in the Woodlands, Texas. It measures 59 protein markers in the blood that distinguish people with Alzheimer's disease from those with Parkinson's disease as well as those without either disease. Data from a study by Sun Health Research Institute in Sun City, Ariz., are expected at the end of August, says Steven Rash, chief executive of Power3. He says the company hopes to launch a test for the public late this year.
It's too soon to tell if these tests are accurate enough to be diagnostic tests or if they may just suggest a higher risk for the disease, Petersen says.
Diagnostic tests that appear reliable in academic research settings may not be as impressive in the general population where "you take all comers," says Dr. P. Murali Doraiswamy, chief of biological psychiatry at Duke University and co-author of the new book "The Alzheimer's Action Plan."
"We should be cautious in applying this technology," he says. "I think people have a right to know, but at the same time people should be counseled fully and not be led into getting these tests without knowing the risks and benefits."
Test may lead to drug
The real value for a diagnostic blood test, at least initially, may be in research. Scientists are also optimistic that an early-diagnosis blood test will spark better drug trials and, ultimately, a blockbuster medication.
Many researchers believe that previous Alzheimer's drug trials have been hindered by inaccurate methods to identify subjects -- people who have the disease rather than some other type of dementia -- and by inferior tools to gauge a drug's effectiveness, such as through cognitive testing or asking people or their family members if the symptoms have improved.
Says McReynolds: "They have been operating in the dark."
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shari.roan@latimes.com
