Blood test could detect Alzheimer's up to 16 years before symptoms begin, study finds

A simple blood test could predict if a patient will develop Alzheimer's disease up to 16 years before symptoms begin, a new study has found.

By measuring changes in the levels of a protein in the blood, called neurofilament light chain (NfL), researchers believe any rise in levels of the protein could be an early sign of the disease, CNN reports, citing a study published Monday in the journal Nature Medicine.

NfL is a "marker in the blood which gives an indication of nerve cell loss in the brain," explained lead researcher Mathias Jucker, professor of cell biology of neurological diseases at the German Center for Neurodegenerative Diseases. ''The more neurofilament you have in the blood, the more brain damage you have," he said.

There is still no effective treatment for Alzheimer's, but Jucker thinks the new blood test will be "very important for clinical studies." He hopes the test will allow researchers to monitor the effectiveness of new treatments before people have started to experience symptoms, by measuring how levels of the protein are affected.

"Alzheimer's disease starts at least a decade, maybe even 20 years, before we have any symptoms," said Jucker, who is also board director at the Hertie Institute for Clinical Brain Research at the University of Tübingen.

There is currently no test doctors can use to conclusively determine whether someone will get Alzheimer's disease and there are a lot of unknowns about its cause. One widely believed theory is that the disease is driven by the production and deposition of beta-amyloid plaques between neurons in the brain.

In the UK, there are 850,000 people living with dementia, Alzheimer's disease is the most common type of this condition, according to the Alzheimer's Society in the UK. According to the US Centers for Disease Control and Prevention, as many as 5 million Americans have Alzheimer's disease.