Doctors may soon use a blood test to screen people for possible signs of dementia, particularly Alzheimer's disease, as researchers inch closer to this diagnostic tool.

Diagnostic Tool For Routine Exams

Doctors currently use brain scans and spinal fluid tests to check for potential signs of Alzheimer's, but these are too expensive or impractical for use in regular check-ups.

A diagnostic tool that can be used during routine exams, when most symptoms of dementia are evaluated, could be a valuable tool for identifying individuals who need more extensive testing.

"We need something quicker and dirtier. It doesn't have to be perfect," said the Alzheimer's Association's chief science officer Maria Carrillo.

Recent developments hint this tool could be on the horizon. At the Alzheimer's Association International Conference on Monday, half a dozen research groups presented results of various experimental tests that could help detect signs of dementia.

Instead of relying on subjective estimates of thinking skills, these tests could detect signs of dementia based on biological factors.

Blood Test With 88 Percent Overall Accuracy 

One of the experimental blood tests measures the abnormal version of the protein forming brain plaques that are the hallmark of the neurological disease.

The test has been shown to be highly accurate at detecting risk for Alzheimer's. It correctly identified 92 percent of people with Alzheimer's and correctly ruled out 85 percent who did not have the condition. This translates to an overall accuracy of 88 percent.

Another test looks at neurofilament light, a protein that serves as a marker of nerve damage. The test may not reveal what disorder a person has but it may help rule one when the symptoms are psychological or caused by other factors.

Prevalence Of Alzheimer's Disease

Figures from the Alzheimer's Association show that 5.8 million people in the United States have Alzheimer's disease. This number is expected to increase to nearly 14 million by the year 2050.

"By 2050, the number of people age 65 and older with Alzheimer's dementia may grow to a projected 13.8 million, barring the development of medical breakthroughs to prevent, slow or cure Alzheimer's disease," the health organization said.