WASHINGTON — US scientists may have found a new way to use a blood test to search for clues of Alzheimer's disease, a discovery that if proven could extend to other ailments, said a study released Thursday.

"If this works in Alzheimer's disease, it suggests it is a pretty general platform that may work for a lot of different diseases," said Thomas Kodadek of The Scripps Research Institute, whose work was published in the journal Cell.

"Now we need to put it in the hands of disease experts to tackle diseases where early diagnosis is key."

There is no cure for Alzheimer's, the most common form of dementia which afflicts five million people in the United States, so the wider public might not see much use in a test for it.

However pharmaceutical companies could use the information to better locate patients for clinical trials.

Kodadek tried a new way to identify signals of disease in the blood, using molecules called peptoids to detect antibodies in the bloodstream of animals and patients with specific diseases.

After isolating more immunoglobulin, a major type of antibody, in mice with a condition similar to multiple sclerosis than he did in healthy mice, he moved on to humans and tested six patients with Alzheimer's, six with Parkinson's and six healthy people.

The tests were able to find three peptoids that captured levels of immunoglobulin in the Alzheimer's patients that was three times higher than the Parkinson's or the control group.

"Dr Kodadek has conceived of a new approach for identifying antibody biomarkers of human disease that bypasses the conventional, but difficult, step of identifying the natural antigens or antigen mimics," said James Anderson of the National Institutes of Health which helped fund the study.

"The results in the paper suggest great potential for using this approach to rapidly develop diagnostic biomarkers for a variety of significant human diseases."

The next step is to try the method on other diseases, such as pancreatic cancer which is swift and deadly.

"It's possible that antibody-based tests might identify such cancers years before they could be detected otherwise," said the study.

Then drug makers would have precious knowledge for developing vaccines against cancer.

"That's the dream scenario," said Kodadek.