A New Blood Test Detects Alzheimer’s Dementia with 93 percent Accuracy

A blood test developed at Washington University School of Medicine in St. Louis has proven highly accurate in detecting early signs of Alzheimer’s disease in a study involving nearly 500 patients from across three continents, providing further evidence that the test should be considered for routine screening and diagnosis.

Our study shows that the blood test provides a robust measure for detecting amyloid plaques associated with Alzheimer’s disease, even among patients not yet experiencing cognitive declines,” said senior author Randall J. Bateman, MD,  Professor of Neurology. “A blood test for Alzheimer’s provides a huge boost for Alzheimer’s research and diagnosis, drastically cutting the time and cost of identifying patients for clinical trials and spurring the development of new treatment options,” Bateman said. “As new drugs become available, a blood test could determine who might benefit from treatment, including those at very early stages of the disease.”

Developed by Bateman and colleagues, the blood test assesses whether amyloid plaques have begun accumulating in the brain based on the ratio of the levels of the amyloid beta proteins Aβ42 and Aβ40 in the blood.

Researchers have long pursued a low-cost, easily accessible blood test for Alzheimer’s as an alternative to the expensive brain scans and invasive spinal taps now used to assess the presence and progression of the disease within the brain.

Evaluating the disease using PET brain scans – still the gold standard – requires a radioactive brain scan, at an average cost of $5,000 to $8,000 per scan. Another common test, which analyzes levels of amyloid-beta and tau protein in cerebrospinal fluid, costs about $1,000 but requires a spinal tap process that some patients may be unwilling to endure.

This study estimates that prescreening with a $500 blood test could reduce by half both the cost and the time it takes to enroll patients in clinical trials that use PET scans. Screening with blood tests alone could be completed in less than six months and cut costs by tenfold or more, the study finds.

Source: https://medicine.wustl.edu/

Simple Diagnostic Tool Predicts Individual Risk of Alzheimer’s

Researchers at Lund University in Sweden have developed an algorithm that combines data from a simple blood test and brief memory tests, to predict with great accuracy who will develop Alzheimer’s disease in the future.

Approximately 20-30% of patients with Alzheimer’s disease are wrongly diagnosed within specialist healthcare, and diagnostic work-up is even more difficult in primary care. Accuracy can be significantly improved by measuring the proteins tau and beta-amyloid via a spinal fluid sample, or PET scan. However, those methods are expensive and only available at a relatively few specialized memory clinics worldwide. Early and accurate diagnosis of AD is becoming even more important, as new drugs that slow down the progression of the disease will hopefully soon become available.

A research group led by Professor Oskar Hansson at Lund University have now shown that a combination of relatively easily acccessible tests can be used for early and reliable diagnosis of Alzheimer’s disease. The study examined 340 patients with mild memory impairment in the Swedish BioFINDER Study, and the results were confirmed in a North American study of 543 people.

A combination of a simple blood test (measuring a variant of the tau protein and a risk gene for Alzheimer’s) and three brief cognitive tests that only take 10 minutes to complete, predicted with over 90% certainty which patients would develop Alzheimer’s dementia within four years. This simple prognostic algorithm was significantly more accurate than the clinical predictions by the dementia experts who examined the patients, but did not have access to expensive spinal fluid testing or PET scans, said Oskar Hansson.

Our algorithm is based on a blood analysis of phosphylated tau and a risk gene for Alzheimer’s, combined with testing of memory and executive function. We have now developed a prototype online tool to estimate the individual risk of a person with mild memory complaints developing Alzheimer’s dementia within four years”, explains Sebastian Palmqvist, first author of the study and associate professor at Lund University.

One clear advantage of the algorithm is that it has been developed for use in clinics without access to advanced diagnostic instruments. In the future, the algorithm might therefore make a major difference in the diagnosis of Alzheimer’s within primary healthcare.

The algorithm has currently only been tested on patients who have been examined in memory clinics. Our hope is that it will also be validated for use in primary healthcare as well as in developing countries with limited resources”, says Sebastian Palmqvist.

Simple diagnostic tools for Alzheimer’s could also improve the development of drugs, as it is difficult to recruit the suitable study partcipants for drug trials in a time- and cost-effective manner. ”The algorithm will enable us to recruit people with Alzheimer’s at an early stage, which is when new drugs have a better chance of slowing the course of the disease”, concludes Professor Oskar Hansson.

The findings are published in Nature Medicine.

Source: https://www.lunduniversity.lu.se/

A Simple Blood Test To Find Early Signs Of Alzheimer’s

A new study found that a simple blood test can detect beta-amyloid protein buildup in a person’s brain years before Alzheimer’s disease symptoms appearHigh amounts of beta-amyloid can clump together and form plaques on the brain, which is strongly associated with Alzheimer’s disease. Other research has found that amyloid plaques can appear as early as 20 years before the first sign of Alzheimer’s symptoms, such as cognitive decline and memory loss.

In the study, 158 adults in their 60s and 70s — most of whom had normal cognitive function — underwent a PET scan to spot amyloid plaque in the brain, and a blood test to measure beta-amyloid in the body. The blood test looked for two forms of beta-amyloid protein: beta-amyloid 42 and beta-amyloid 40. When beta-amyloid begins to build up, the ratio between the two proteins changes, and the blood test detects this.

The researchers labeled each blood test result as either amyloid positive or negative. They then compared them with the PET scans. They found that the PET scans confirmed the blood test results  88% of the time. When other risk factors were included, such as age and the appearance of the gene variant ApoE4 (which also is linked to a higher risk for Alzheimer’s), the test’s accuracy rose to 94%.

While there is some debate as to whether amyloid plaque actually causes Alzheimer’s, a simple blood test that indicates you may be at a higher risk of the disease would be one more reason to adopt lifestyle changes. The researchers added that they expect the blood test to be available within a few years.

The results were published online Aug. 1, 2019, by the journal Neurology.

Source: https://www.health.harvard.edu/