New Test Promises Fast, Simple and Effective Alzheimer's Diagnosis

Scientists have developed a blood test that can help detect Alzheimer’s disease very accurately, even in the early stages of the disease. This new test measures a protein called p-tau217, which is linked to brain damage caused by Alzheimer’s. Unlike more expensive and difficult tests, such as imaging or spinal fluid, this blood test is simpler and can be done in regular labs. This could make early diagnosis much easier, allowing more people to receive the right treatment at the right time.

In recent years, scientists have made great strides in creating blood tests that can help detect Alzheimer’s disease, even before symptoms become too severe.

One of the most promising markers found in the blood is called p-tau217, a protein linked to brain damage caused by the disease. Measuring this protein in the blood, either alone or in comparison with other substances such as Aβ42, has shown good results in detecting the presence of Alzheimer’s.

Currently, the most accurate tests for Alzheimer's are still expensive and difficult to perform, such as collecting fluid from the spine (cerebrospinal fluid) or sophisticated imaging tests, such as PET.

These tests are not always available, especially in regular hospitals. Therefore, the possibility of detecting the disease with a simple blood test is a major revolution.

Some laboratory techniques, such as mass spectrometry, can already do this accurately, but they require expensive equipment and specialized teams. On the other hand, tests called “immunoassays”, which are already used to diagnose many diseases in regular laboratories, are being adapted to detect Alzheimer's as well, which could make these tests much more accessible.

Correctly detecting Alzheimer's is a major challenge, and many patients are misdiagnosed, especially when biomarkers of the disease are not used. This happens frequently in primary care offices, where doctors do not always have access to more sophisticated tests.

Therefore, making blood tests automated and accessible could help many professionals diagnose the disease more accurately, quickly and safely.

This advance is even more important now that some countries are already offering treatments for the early stages of Alzheimer's. These medications require confirmation that the patient actually has the disease, which can only be done with the help of biomarkers.

In addition, early diagnosis allows treatment to begin before the brain is more affected, increasing the chances of better results. One of the most promising tests is Lumipulse, which is already authorized for use with spinal fluid and is now being adapted for blood.

Lumipulse is a fully automated laboratory testing technology used to detect certain health problems by analyzing samples from the body, such as blood or cerebrospinal fluid (the fluid that circulates in the brain and spinal cord).

In the case of Alzheimer's, Lumipulse is used to measure specific proteins linked to the disease, such as p-tau217, which accumulates in the brain when there are early signs of the condition. This test works in a similar way to other blood tests that you do in regular laboratories.

The big advantage of Lumipulse is that it is fast, accurate and can be performed in many laboratories around the world, without the need for expensive machines or rare specialists. It helps doctors detect Alzheimer's with greater confidence, especially in the early stages when treatment can be most effective.

In this study, researchers from Lund University, Sweden, aimed to test a version of this test that uses blood samples to see if it can actually detect the disease accurately.

They analyzed samples from more than 1,700 people with symptoms of memory loss from different European countries, Malmö (Sweden, n = 337), Gothenburg (Sweden, n = 165), Barcelona (Spain, n = 487) and Brescia (Italy, n = 230), and a primary care cohort in Sweden (n = 548), both from specialist clinics and primary care.

The results showed that this blood test can identify Alzheimer's disease with high accuracy, especially in people under 80 years of age. In specialist clinics, the accuracy was up to 91%, and in primary care, it reached 85%.

All p-tau217 levels differed significantly (P < 0.0001) between participants with positive and negative AD pathology in all cohorts, namely, Malmö (n = 337) (a), Gothenburg (n = 165) (b), Barcelona (n = 487) (c), Brescia (n = 230) (d) and in primary care (Sweden) (n = 548) (e)

Performance was slightly lower in people over 80 years of age, but still quite useful. Other conditions, such as diabetes, kidney disease, gender and the stage of memory loss, did not affect the accuracy of the test. The researchers also tested combinations of markers to further improve the results and reduce “undefined” cases.

In short, this automated blood test for Alzheimer’s is a very important step towards making the diagnosis of the disease simpler, faster and more accessible. It could be especially useful for primary care physicians and allow more people to have access to accurate diagnosis and early treatment, greatly improving the quality of life of patients.

READ MORE:

Plasma phospho-tau217 for Alzheimer’s disease diagnosis in primary and secondary care using a fully automated platform

Sebastian Palmqvist, Noëlle Warmenhoven, Federica Anastasi, Andrea Pilotto, Shorena Janelidze, Pontus Tideman, Erik Stomrud, Niklas Mattsson-Carlgren, Ruben Smith, Rik Ossenkoppele, Kübra Tan, Anna Dittrich, Ingmar Skoog, Henrik Zetterberg, Virginia Quaresima, Chiara Tolassi, Kina Höglund, Duilio Brugnoni, Albert Puig-Pijoan, Aida Fernández-Lebrero, José Contador, Alessandro Padovani, Mark Monane, Philip B. Verghese, Joel B. Braunstein, Silke Kern, Kaj Blennow, Nicholas J. Ashton, Marc Suárez-Calvet and Oskar Hansson

Nature Medicine. 9 April 2025

DOI: 10.1038/s41591-025-03622-w

Abstract

Global implementation of blood tests for Alzheimer’s disease (AD) would be facilitated by easily scalable, cost-effective and accurate tests. In the present study, we evaluated plasma phospho-tau217 (p-tau217) using predefined biomarker cutoffs. The study included 1,767 participants with cognitive symptoms from 4 independent secondary care cohorts in Malmö (Sweden, n = 337), Gothenburg (Sweden, n = 165), Barcelona (Spain, n = 487) and Brescia (Italy, n = 230), and a primary care cohort in Sweden (n = 548). Plasma p-tau217 was primarily measured using the fully automated, commercially available, Lumipulse immunoassay. The primary outcome was AD pathology defined as abnormal cerebrospinal fluid Aβ42:p-tau181. Plasma p-tau217 detected AD pathology with areas under the receiver operating characteristic curves of 0.93–0.96. In secondary care, the accuracies were 89–91%, the positive predictive values 89–95% and the negative predictive values 77–90%. In primary care, the accuracy was 85%, the positive predictive values 82% and the negative predictive values 88%. Accuracy was lower in participants aged ≥80 years (83%), but was unaffected by chronic kidney disease, diabetes, sex, APOE genotype or cognitive stage. Using a two-cutoff approach, accuracies increased to 92–94% in secondary and primary care, excluding 12–17% with intermediate results. Using the plasma p-tau217:Aβ42 ratio did not improve accuracy but reduced intermediate test results (≤10%). Compared with a high-performing mass-spectrometry-based assay for percentage p-tau217, accuracies were comparable in secondary care. However, percentage p-tau217 had higher accuracy in primary care and was unaffected by age. In conclusion, this fully automated p-tau217 test demonstrates high accuracy for identifying AD pathology. A two-cutoff approach might be necessary to optimize performance across diverse settings and subpopulations.