7 min

Revolutionary diagnostic blood test for Alzheimer’s

Wallenberg Clinical Scholar Oskar Hansson has researched Alzheimer’s disease for just over twenty years. He has developed a number of methods for earlier, more accurate diagnosis. His team has been essential for the development of simple blood tests for the disease.

Oskar Hansson

Consultant and Professor of Neurology

Wallenberg Clinical Scholar, prolongation grant 2023

Lund University

Research field:
Neurodegenerative diseases

It has been known since the early 1980s that Alzheimer’s disease is caused by changes in the brain: build-up of plaque and clumps of two proteins called beta-amyloid and tau. So when Hansson chose his research field in the 1990s he thought that success could be just around the corner.

“There was potential for a major breakthrough within ten to twenty years – there was much that had not happened in terms of diagnostics and treatment. I thought it was exciting.”

Ten years passed, and then another ten, without any significant progress in treatments for the disease. It was not until the fall of 2022 that a breakthrough was made.

“That year saw the launch of a drug that seems to slow the progress of the disease in the brain, so that clinical deterioration is about 30 percent slower. This might not sound like much, but you have to look at the big picture: it’s the first time we’ve been able to slow down the disease,” says Hansson, who is a consultant, professor of neurology at Lund University and a Wallenberg Clinical Scholar.

The drug has not yet been approved in Europe, but has been greenlighted in some countries, including the U.S., China and Japan. Recipients of the drug have been in a late stage of the disease, suffering cognitive decline for at least a decade. Hansson is hopeful that the effect will be even better if therapy begins earlier, preferably before the patient displays symptoms.

“I see this as the first tentative step toward a future cure.”

Biomarker pioneer

These recent developments have made his own research field hotter than ever. Hansson’s team is developing techniques for diagnosing Alzheimer’s as early and as accurately as possible, and for monitoring the disease or the impact of treatment.

The main focus is on biomarkers – substances whose concentrations in the body change due to disease. But the team is also working on PET (Positron Emission Tomography) brain imaging, and on genetic factors and cell protein content.

“We want to understand the molecular changes associated with the disease. This is critical for diagnosis and prognosis, and may also lay the foundations for new therapies.”

Just over twenty years ago Hansson’s team, working with researchers in Gothenburg led by Professor Kaj Blennow, were pioneers in the field of biomarkers in spinal fluid. These markers are now used throughout the world to diagnose Alzheimer’s. The Swedish researchers also developed a method of combining the markers with PET scans, enabling them to identify sub-categories of the disease.

Much better diagnostic accuracy

Over the past five years the team has primarily focused on biomarkers in blood. The field has been given a real boost thanks to new technology developed by the pharmaceutical industry, which has greatly improved the accuracy of measurements. The researchers have now developed a method of measuring tau in blood, where the concentration is much lower than in the brain and spinal fluid. The test is as accurate as current diagnostic methods, but is much cheaper and simpler. Hansson believes it will revolutionize diagnostics throughout the world.

His team is now conducting a study to find out how the method would work in primary health care. Some thirty health centers in Skåne, southern Sweden, are taking part. Doctors there are taking blood samples from patients with suspected memory loss and sending them to the researchers, who follow up the referrals with further examination of the patients.

“The blood samples are sent to us by standard delivery, and have yielded a diagnostic accuracy rate of over 90 percent for Alzheimer’s. The cognitive tests that physicians normally use have an accuracy of about 50 to 60 percent. I think this clearly demonstrates that the blood samples will have a huge impact, and will lead to more widespread successful diagnosis, globally and in Sweden.”

A project taking place in parallel with the study involves 4,000 symptom-free people in the far south of Sweden. They are being screened using the new blood test. The aim is to identify those with early pathological changes in the brain, and offer them the opportunity to take part in clinical drug trials. The researchers are also evaluating multiple blood markers, with the aim of eventually using them to diagnose other diseases of the brain.

Growing interest in the field

Hansson spends 70 percent of his time on research, and the remainder on clinical work. This gives him an insight into priorities among patients themselves.

“The type of patients we are dealing with have for a long time been regarded as low status patients. Dementia has been regarded as a natural part of ageing, and many people underestimate the importance of this awful disease. When a therapy was announced it was discussed whether it was ‘clinically meaningful’ to slow down the rate of cognitive decline by 30 percent. Would this have been said about a treatment for cancer...?”

Over the past few years we’ve seen how incredibly important it is for Alzheimer’s sufferers to be diagnosed, that they understand what is causing their symptoms, and that they receive the support they need – even though there is – as yet – no cure for the disease.

But Hansson thinks that interest appears to be growing. He has received considerable media attention, both for the team’s work, and as an Alzheimer’s expert. This benefits the research field, but personally he is somewhat ambivalent.

“It draws attention away from other important areas of course, and I have never sought the limelight; I’m driven by an overriding curiosity.”

He often works from the morning far into the night, and acknowledges that this is hardly sustainable in the long term.

“I’ve been energized by the team’s success. But I have a long-term plan to delegate more of the responsibility. If nothing else, I need to find time for other interests I can pursue when I eventually retire…”

Text Lisa Kirsebom
Translation Maxwell Arding
Photo Åsa Wallin