Summary:
A large international study found that a simpler blood test method using plasma P-tau217 can accurately detect Alzheimer’s disease, making advanced diagnostics more accessible.
Three key takeaways:
- The simpler test method showed 92–94% accuracy using a two-cut-off approach.
- Accuracy was lower (83–87%) in the oldest patients when only one cut-off was used.
- This easier analysis could allow small hospitals worldwide to diagnose Alzheimer’s more reliably.
Previous studies have examined the accuracy of the blood test measuring plasma P-tau217, using more specialized analytical methods such as mass spectrometry. These blood tests for the diagnosis of Alzheimer’s disease are used clinically in the US and are expected to be authorized in many parts of the world.
Multicentre Study Evaluates Alzheimer’s Detection Method
A multicentre study conducted in three countries has now evaluated a simpler method of analysis. The aim was to investigate the accuracy in everyday clinical practice and the study was conducted both in primary care and in more specialized memory clinics in Sweden (Malmö and Gothenburg), Italy (Brescia) and Spain (Barcelona). In total, 1,767 people with cognitive symptoms were included in the study.
“Even with the simpler method of analysis, the blood test gives highly accurate results for Alzheimer’s disease pathology,” says Sebastian Palmqvist, associate professor and senior lecturer in neurology at Lund University and senior consultant at Skåne University Hospital, who led the study together with Oskar Hansson.
Two Cut-offs for Blood Test Ups Accuracy
The researchers used two cut-offs as the main method to determine whether the blood sample should be interpreted as positive or negative. If a test result is above the upper cut-off, it is classified as positive, i.e. the presence of Alzheimer’s disease pathology. If it is below the lower cut-off, it is classified as negative. Values between these cut-offs fall into a grey area and are not assessed in the analysis.
“When the method was tested in patient groups, the accuracy was between 92% and 94%,” says Noëlle Warmenhoven, researcher and doctoral student in clinical memory research at Lund University, and first co-author. “This is very promising as this method is likely to become one of the more widely used methods in clinical practice worldwide, including Sweden.”
The results were slightly less reliable (83%-87%) for the oldest group included in the study if only one cut-off was used.
“For some reason, we see a slightly lower accuracy in the older group, but this deterioration was not visible when using the approach with two cut-offs,” says Sebastian Palmqvist.
The simpler method of analysis means that a blood test for Alzheimer’s disease can be introduced even in small hospitals.
“This makes the improved diagnostics more accessible to substantially more people worldwide. This is of great importance, as the disease is often misdiagnosed without biomarkers like this, and currently only a very small percentage of sufferers have access to these high-precision diagnostics,” says Oskar Hansson.
Featured Image: Sebastian Palmqvist, associate professor of neuroscience and senior lecturer in neurology specialising in cognition at Lund University, and senior consultant at Skåne University Hospital. Image: Tove Smeds
