Australian National University researchers have developed a method of linking a person's deteriorating brain health and the likelihood of getting Alzheimer's.

Australians living with mild cognitive impairment could know five years in advance whether they are at high risk of developing Alzheimer's disease, according to new research.

Researchers from the Australian National University on Wednesday announced they have developed a simple method of linking a person's deteriorating brain health and the likelihood of them getting Alzheimer's.

They examined the blood biomarker called plasma neurofilament light chain (pNFL), which measures fragments of dying neurons from the brain that have trickled into the bloodstream, as well as a patient's mini-mental state examination scores to predict the likelihood of Alzheimer's.

"We have the ability to see into the future and estimate whether they are at low, moderate or high risk," Professor Nicolas Cherbuin, head of the ANU Centre for Research on Ageing, Health and Wellbeing, said in a statement.

The blood sample is taken by needle and is less invasive and more accessible than other diagnostic procedures, such as MRI and PET scans and spinal taps.

Professor Cherbuin hopes pNFL measurements will become more widely used in the healthcare sector in the future.

"We hope, through this research, we're able to provide more choices to patients and their families by giving them plenty of time to introduce positive lifestyle changes and hopefully delay the onset of this terrible disease for as long as possible," he said.

The ANU research team used data from the Alzheimer's Disease Neuroimaging Initiative and looked at the brain health of 440 patients living with mild cognitive impairment to accurately make their predictions.

Alzheimer's disease is the most common form of dementia, affecting up to 70 per cent of all people with dementia.

Almost 500,000 Australians live with dementia and that number is expected to double in the next 25 years.