A new blood test claiming to detect brain plaque and help diagnose Alzheimer's disease goes on sale.

This could make it easier for people to learn whether they have dementia. However, it also raises concerns about the accuracy and impact of such huge news in the medical field, as reported by NBC News.

Independent experts are wary as key test results have not been published, and the test has yet to be approved by the U.S. Food and Drug Administration (FDA).

The blood test is being sold under more general rules for commercial labs. However, it has been agreed that a simple test that could be done in a doctor's office has long been needed. 

Alzheimer's Cases

More than five million people in the U.S. and millions more worldwide have Alzheimer's, which is the most common type of dementia. 

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People must have symptoms of the disease to be diagnosed with it. Its symptoms include memory loss and an evident build-up of a protein called beta-amyloid in the brain.

The way to measure the so-called protein is through an expensive PET brain scan, which usually is not covered by insurance.

As a result, a lot of people cannot afford to get one and are left wondering if their problems are due to normal aging, Alzheimer's, or other causes.

C2N Diagnostics' blood test hopes to fulfill that need. The company's founders are Drs. David Holtzman and Randall Bateman of Washington University School of Medicine. Both doctors led the research, which produced the test. 

How much does it cost? 

The test is not for general screening or for people that do not have any symptoms. It is intended for people 60 and older and those who have thinking problems and are being evaluated for Alzheimer's.

The blood test is not covered by insurance or Medicare. The company sells the blood test, starting from $1,250, and offers discounts based on income. 

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Only doctors can also order the tests, and results can be known within 10 days. The blood test is currently being sold in some states in the U.S. and was recently cleared for sale in Europe.

The blood test also measures two types of amyloid particles plus various protein forms that reveal someone has a gene that raises the disease's risk. These factors are examined together with other variables such as age.

Patients are also given a score ranging from low, medium, or high likelihood of having amyloid buildup in the brain.

"There are a thousand things that can cause someone to be cognitively impaired, from vitamin deficiencies to medications," Holtzman said in an NBC News report. 

He added that he believes that the test is no different from the testing they do now, except that it's a blood test rather than a brain scan.

"And those are not 100% accurate either," he added.

Meanwhile, the company has not yet published any data on the test's accuracy, but the doctors have published on the amyloid research leading to the test.