Apparently there are 18 'signaling' proteins in plasma that can be used to help diagnose the presence of Alzheimer's disease, according to a study reported in Nature Medicine. (A signaling protein is, as its name implies, a string of amino acids that allows a particular protein to communicate or move within the cell.)

Scientists assayed plasma from 85 Alzheimer's disease and from 79 non-Alzheimer subjects, looking for 120 known signaling proteins. Using half the samples, they found 18 signaling proteins that distinguished the Alzheimer's plasma samples from the others. Then they tested the remaining samples to see how well the chosen proteins were able to select the Alzheimer's. They found the testing procedure recognized 90% of the Alzheimer's plasma and 88% of the non-Alzheimer's.

In another test, the signaling proteins were able to identify patients with mild cognitive impairment who went on to develop Alzheimer's in the next 2-6 years with 91% accuracy, and achieved 100% success in recognizing mild cognitive impairment subject who didn't develop Alzheimer's.

There will be need for more studies in larger numbers of individuals before this test (or one very like it) can be approved for marketing by the FDA. The initial tests have been made by the company that discovered and manufactured the components - Satoris Inc., meaning that independent trials are necessary. By the time such a test is available, we may have made up our minds whether we really want to know if we have, or are going to get, Alzheimer's. Hopefully, there will be better treatments available by then, too.