A blood test breakthrough could make it easier to identify brain diseases such as Alzheimer's and Parkinson's, according to research.

The technology, which has been successfully tested on human patients, could also spot hard-to-detect cancers and other diseases earlier.

The new approach involves using synthetic molecules called peptoids to "fish" for disease-specific antibodies in the blood. It could revolutionise the way blood tests are conducted.

Traditionally, the tests detect immune system antibodies that target natural proteins linked to certain diseases. The proteins, known as "antigens" can be attached to a variety of diseases and viruses.

Before this breakthrough there has been no way of identifying disease-specific antibodies without finding the antigens which trigger their production. But this has often proved to be a virtually impossible obstacle to overcome.

The new technique manages to evade these problems by substituting artificial peptoids for antigens.

One promising application is in the diagnosis of dangerous, hard-to-detect cancers, such as pancreatic cancer. Blood tests based on peptoid technology could conceivably allow such diseases to be diagnosed much earlier, increasing the chances of successful treatment.

Peptoids might also help guide scientists in their search for natural antigens that could be used in cancer vaccines.

The research has been published in the journal Cell.

Professor Thomas Kodadek, from Scripps Research Institute in La Jolla, California, who led the research, said: "If this works in Alzheimer's disease, it suggests it is a pretty general platform that may work for a lot of different diseases."

Copyright © Press Association 2011

Cell