New Blood Test May Diagnose Alzheimer's Before Patients Show Symptoms

Researchers from across the country who collaborated on Alzheimer’s Disease work may have found a way to detect the disease with a blood test before patients even exhibit symptoms.

Alzheimer's is an incurable degenerative disease that impacts the brain causing confusion, memory loss and eventually leads to the loss of thinking skills that are key to simple task completion, according to the National Institute on Aging. Estimates put the Alzheimer's population in the United States around 5 million and suggest that the population will grow.

The test actually does more than detect Alzheimer’s, it can also distinguish between Alzheimer’s, Parkinson’s and regular control samples. This distinguishability is important because it means the test is sensitive to more than neurodegeneration which can be present with aging and other neurodegenerative diseases that might develop. The test is able to distinguish between these diseases by focusing on the white blood cells or leukocytes, according to a press release regarding the research and published study. Genetic information is derived from specific segments of RNA also called transcripts.

The hope is that by using the blood test to identify the disease in patients before it’s able to degenerate the brain to the point where the patient begins to show symptoms, the progress of the Alzheimer’s could be slowed or even stopped. The difficulty detecting and diagnosing the disease has always previously been a major issue.

The test has a sensitivity rate between 71 and 87 percent which means it could correctly identify those who had been diagnosed with the disease. It did this by examining the RNA transcripts which acted as a biomarker. To identify these transcripts the scientists involved used one technique called a cDNA array and one called a reverse transcriptase polymerase chain reaction. This then allowed them to create a suite or array of transcripts that they used to diagnose.

These methods were able to distinguish patients most likely to develop Alzheimer’s from the control group with 93 percent accuracy. The experimental design of the study allowed the researchers to look at multiple sample populations as well as multiple samples. There were 177 blood samples studied as well as 27 brain tissue samples to determine the results all broken down into different studies to replicate the findings within the one study. This increases the chances of the results having a high reliability.

RNA transcripts linked with stress and inflammation as well as sequences that showed evidence of having undergone post-transcriptional modification, strongly correlated with the presence of Alzheimer’s markers. Meaning those transcriptions could be used as a means of fairly easy testing.

Previous studies have linked Alzheimer’s and dementia to stress on the body due to poor sleep or a lack thereof. However, the diagnosis of the disease as well as the prediction of it in patients is still a science that researchers have yet to perfect. But the new blood test technology shows promise. Future studies and larger samples sizes will be necessary to fully determine the implications of the test.