It's still impossible to diagnose Alzheimer's disease for certain until the patient has died, via autopsy. But a new test, being described for the first time today in the online edition of Annals of Neurology, could change all that. By analyzing 2000 different proteins in the spinal fluid of 34 confirmed Alzheimer's victims who subsequently died with proteins in a like number of people without the disease, researchers at Cornell University and Weill Cornell Medical College identified 23 proteins that are 90% effective in identifying the Alzheimer's sufferers.

What it means: This test needs to be replicated before it's considered reliable. But if it is, it should have a clear advantage over existing tests, which have depended on single chemical markers; with 23, the scientists believe they have a much better shot at identifying the disease--and the autopsy results show they're clearly on to something. And while many cases of Alzheimer's are so clearcut there's no need for such a test,  Dr. Norman Relkin, a co-author of the study,told TIME's Christine Gorman, "there are still cases where even in expert hands, or multiple experts looking at a patient, you don't know what's causing the dementia. This type of a test would be very helpful for that."

From the Archives:

October 12, 2006: Marijuana Vs. Alzheimer's
Oct. 4, 2006: Anti-Alzheimer's Spice