Blood test detects Alzheimer’s accurately

We have heard it all before – the development of blood tests that claim to help in the detection of Alzheimer’s disease; but New Jersey scientists have developed a “simple” blood test that alleges to identify the presence of the neurological disease with 96% accuracy.

The test’s developer, Dr Robert Nagele, who is a professor of medicine at the University of Medicine and Dentistry, claims the test has a high accuracy rate with the possibility of the disease being detected from a single drop of blood.

Researchers report the blood test is able to correctly differentiate between those who have Alzheimer’s and those who have similar conditions, such as Parkinson’s disease.

Dr Nagele and his colleagues analysed blood samples from 50 people already diagnosed with Alzheimer’s disease and 40 who did not have the disease. They also analysed blood samples from 30 breast cancer patients and 29 patients with Parkinson’s disease, in order to ascertain that their blood test could specifically identify those with Alzheimer’s and differentiate them from patients with these other conditions.

“Parkinson’s and Alzheimer’s are very close in terms of their pathology,” Dr. Nagele explains. “Neurons are dying in both cases,” he says.

Based on this analysis, Dr Nagele and his colleagues identified certain antibodies in the blood specific to Alzheimer’s disease; many of which they believe may relate to Alzheimer’s.

The findings, published in this month’s issue of PLoS ONE, revealed the presence of 10 antibodies in the blood which helped to successfully identify 96% of those who had Alzheimer’s disease. The absence of these 10 antibodies also successfully identified 92.5% of those in the study who did not have Alzheimer’s.

Dr Nagele says Alzheimer’s is “widely believed” to begin up to 10 or more years before symptoms actually appear and are noticeable; however, before symptoms occur, brain changes are already under way.

“Brain cells die and when they die, they pop and explode, like a water balloon breaking and the contents of those dying cells are released partially back into the blood.

“Your body makes antibodies against the cell debris. We believe that happens so it can facilitate the clean-up of the cell debris,” he says.

According to researchers, this may explain why certain antibodies found in the blood were able to predict the presence of Alzheimer’s.

The researchers caution, however, their study so far has only shown an ability to identify those who already have been diagnosed as having Alzheimer’s (based on their apparent symptoms and other existing means) out of a small sample of people. The test has not yet been proven to be able to detect the disease in advance before symptoms appear; but Dr Pappas hopes this will soon be the case.

Doctors now use observation of apparent symptoms of the disease, brain imaging, psychiatric tests, behaviour evaluation, and other means to diagnose the disease indirectly.

For many years, scientists around the world have been working on developing blood tests and other methods, such as cerebral spinal fluid tests, to diagnose Alzheimer’s. At last month’s Alzheimer’s Association International Conference, Australian researchers reported positive results from a blood test they were developing; which detects Alzheimer’s by determining the amount of amyloid plaque, a substance associated with the disease, found in the patient’s brain.