Test For Early Alzheimer's In Late Development

First, a small sample of cells is removed from a patient's skin at a doctor's office or testing center and shipped to the institute. There, scientists grow the skin cells in a glass dish and add a substance to stimulate an enzyme called PKC to make the protein combine with the element phosphorous inside the skin cells. If too much phosphorous ends up in the combination, then the patient has Alzheimer's, Alkon said.

So far, the test has been tried on more than 300 patients at 15 hospitals, including 42 for whom the Alzheimer's diagnosis was later confirmed by an autopsy showing the disease's signature pattern of brain damage — the only definitive way to diagnose it.

The test was 98 percent accurate on the autopsied patients. But of those, only 11 had early Alzheimer's, as very few people die within three or four years of the disease starting. Alkon hopes to test thousands more patients before his diagnostic test is marketed.

Dr. Ralph Nixon, vice chairman of the Alzheimer's Association's medical and scientific advisory council, said the institute's test needs more evaluation, particularly among patients with early symptoms, to determine its accuracy. Researchers elsewhere also need to be able to duplicate the results.