Experts predict that the discovery could lead to early treatment to prevent the disease harming patients.
At present doctors have no way of picking up MS before symptoms develop and patients are frequently diagnosed quite late.
But now a team of Israeli doctors and scientists have found "chemical markers" on blood that will lead to a test for the disease.
Professor Anat Achiron, of Tel Aviv University's Faculty of Medicine, has uncovered a way of detecting MS years before the illness hits sufferers.
"We are not yet able to treat people with MS to prevent the onset of the disease but knowledge is power," said Professor Achiron.
"Every time we meet a new patient exhibiting symptoms of MS, we must ask ourselves how long this has been going on.
"We can diagnose MS by brain MRI scans, but we've never been able to know how 'fresh' the disease is.”
Her findings are published in the journal Neurobiology of Disease.
If doctors can predict the onset of MS early enough, intervention therapies using drugs such as Copaxone or beta-interferon drugs that stave off MS symptoms might be used.
"We theorised that if we looked at the gene expression signature of blood cells in healthy people, we could look for possible biological markers that characterise those who subsequently developed MS,” said Professor Achiron
Multiple sclerosis has devastating affect on lives with more than 100,000 sufferers in the UK and two million worldwide.
The disease is more prevalent in cold climates and attacks twice as many women as men. There is currently no cure although some drugs lessen the effects of symptoms.
Examining blood samples of 20, 19-year-old Israelis who were inducted into the army as healthy soldiers, and the nine of them who later developed MS, Israeli researchers were able to examine thousands of genes for markers that showed a difference in those who developed MS and those who didn’t.
"Those who will develop MS will show a different blood signature from those who will not," said Professor Achiron.
These early genetic markers may now be used to test for MS up to nine years before healthy young adults start developing symptoms.
And because MS is thought to have a genetic component and a tendency to be found in siblings, doctors believe they will initially be used as a tool for testing brothers and sisters of patients.
Helen Yates, Multiple Sclerosis Resource Centre Chief Executive said, “Any test that can identify MS very early on in the disease course is very welcome.
“One of the most important factors in MS is to treat, by whatever chosen method, as early as possible to prevent further damage within the nervous system.
"We welcome this research and hopes that the test progresses to become a standard part of the diagnostic toolkit."