Blood test offers hope for early detection of Alzheimer's

Blood test offers hope for early detection of Alzheimer's

A simple blood test has been shown to detect Alzheimer’s disease in routine health care settings with up to 90% accuracy, according to Swedish researchers.

The findings were presented at the Alzheimer’s Association International Conference in Philadelphia on Sunday.

The test works by measuring the levels of Plasma Phospho-Tau217, a biomarker that is linked to the presence of Alzheimer’s pathology in the brain.

It has been shown to detect the disease even before the person begins experiencing symptoms, researchers say.

"The tested blood test can detect Alzheimer’s disease with high accuracy even in real-life settings in primary care," said study author Oskar Hansson, M.D., head of the Clinical Memory Research Unit at Lund University, Sweden, in an email to Fox News Digital.

It is currently difficult for primary care physicians to diagnose Alzheimer’s disease due to a lack of adequate tools, he said. 

In the most recent study — also published in the journal JAMA — 1,213 people who were experiencing mild memory loss were evaluated by either primary care doctors or memory specialists. 

The patients then underwent both the blood test and cerebrospinal fluid tests, and researchers compared the results.

"Primary care doctors’ accuracy in identifying Alzheimer’s disease was 61%, while specialist physicians were correct 73% of the time," study author Sebastian Palmqvist, associate professor of neurology at Lund University, stated in a press release.

By comparison, the blood test had an accuracy of 90%.

"I was surprised by how well the blood test worked in real-life settings in primary care, where the patients are older and have more comorbidities like kidney disease, which can affect the blood test results," Hansson told Fox News Digital.

The main limitation of the research was that it was only conducted in Sweden. 

"We need studies in the U.S. and other countries to better understand the generalizability of the findings," Hansson said.

"I think it will take one or two years before there are clinical guidelines in place for use of blood tests in primary care."

Looking ahead, there is a need for clear guidelines on how doctors should use these tests in clinical practice, according to the researchers. 

"My prediction is that highly accurate blood tests will very soon be recommended for use in patients with cognitive impairment who are assessed at clinics specialized in memory disorders," Hansson said. 

This could help to reduce the need for more advanced and expensive methods, like PET scans and cerebrospinal tests.

"I think it will take one or two years before there are clinical guidelines in place for use of blood tests in primary care," Hansson also noted. 

The researchers do not currently recommend screenings for "cognitively normal people" — as there are not any approved treatments for people with Alzheimer’s disease pathology who do not have cognitive impairment, the researcher said.

Added Hansson, "Further, we propose that the blood test should be used as an adjunct to, and not replacement for, the clinical assessments used today."

Approximately one in five women and one in 10 men develop dementia due to Alzheimer’s disease, according to the Alzheimer’s Association.

The condition is misdiagnosed in 25% to 35% of patients who are treated at specialized clinics, previous studies have shown — and researchers believe that number is even higher for patients assessed by their primary care physicians.

https://www.foxnews.com/health/alzheimers-blood-test-detects-disease-accuracy-routine-doctors-appointments-study

Janelidze S, Barthélemy NR, Salvadó G, Schindler SE, Palmqvist S, Mattsson-Carlgren N, Braunstein JB, Ovod V, Bollinger JG, He Y, Li Y, Raji CA, Morris JC, Holtzman DM, Ashton NJ, Blennow K, Stomrud E, Bateman RJ, Hansson O. Plasma Phosphorylated Tau 217 and Aβ42/40 to Predict Early Brain Aβ Accumulation in People Without Cognitive Impairment. JAMA Neurol. 2024 Jul 28. doi: 10.1001/jamaneurol.2024.2619. Epub ahead of print. PMID: 39068669.

Abstract

Importance: Phase 3 trials of successful antiamyloid therapies in Alzheimer disease (AD) have demonstrated improved clinical efficacy in people with less severe disease. Plasma biomarkers will be essential for efficient screening of participants in future primary prevention clinical trials testing antiamyloid therapies in cognitively unimpaired (CU) individuals with initially low brain β-amyloid (Aβ) levels who are at high risk of accumulating Aβ.

Objective: To investigate if combining plasma biomarkers could be useful in predicting subsequent development of Aβ pathology in CU individuals with subthreshold brain Aβ levels (defined as Aβ levels <40 Centiloids) at baseline.

Design, setting, and participants: This was a longitudinal study including Swedish BioFINDER-2 (enrollment 2017-2022) and replication in 2 independent cohorts, the Knight Alzheimer Disease Research Center (Knight ADRC; enrollment 1988 and 2019) and Swedish BioFINDER-1 (enrollment 2009-2015). Included for analysis was a convenience sample of CU individuals with baseline plasma phosphorylated tau 217 (p-tau217) and Aβ42/40 assessments and Aβ assessments with positron emission tomography (Aβ-PET) or cerebrospinal fluid (CSF) Aβ42/40. Data were analyzed between April 2023 and May 2024.

Exposures: Baseline plasma levels of Aβ42/40, p-tau217, the ratio of p-tau217 to nonphosphorylated tau (%p-tau217), p-tau231, and glial fibrillary acidic protein (GFAP).

Main outcomes and measures: Cross-sectional and longitudinal PET and CSF measures of brain Aβ pathology.

Results: This study included 495 (BioFINDER-2), 283 (Knight ADRC), and 205 (BioFINDER-1) CU participants. In BioFINDER-2, the mean (SD) age was 65.7 (14.4) with 261 females (52.7%). When detecting abnormal CSF Aβ-status, a combination of plasma %p-tau217 and Aβ42/40 showed better performance (area under the curve = 0.949; 95% CI, 0.929-0.970; P <.02) than individual biomarkers. In CU participants with subthreshold baseline Aβ-PET, baseline plasma %p-tau217 and Aβ42/40 levels were significantly associated with baseline Aβ-PET (n = 384) and increases in Aβ-PET over time (n = 224). Associations of plasma %p-tau217 and Aβ42/40 and their interaction with baseline Aβ-PET (%p-tau217: β = 2.77; 95% CI, 1.84-3.70; Aβ42/40: β = -1.64; 95% CI, -2.53 to -0.75; %p-tau217 × Aβ42/40: β = -2.14; 95% CI, -2.79 to -1.49; P < .001) and longitudinal Aβ-PET (%p-tau217: β = 0.67; 95% CI, 0.48-0.87; Aβ42/40: β = -0.33; 95% CI, -0.51 to -0.15; %p-tau217 × Aβ42/40: β = -0.31; 95% CI, -0.44 to -0.18; P < .001) were also significant in the models combining the 2 baseline biomarkers as predictors. Similarly, baseline plasma p-tau217 and Aβ42/40 were independently associated with longitudinal Aβ-PET in Knight ADRC (%p-tau217: β = 0.71; 95% CI, 0.26-1.16; P = .002; Aβ42/40: β = -0.74; 95% CI, -1.26 to -0.22; P = .006) and longitudinal CSF Aβ42/40 in BioFINDER-1 (p-tau217: β = -0.0003; 95% CI, -0.0004 to -0.0001; P = .01; Aβ42/40: β = 0.0004; 95% CI, 0.0002-0.0006; P < .001) in CU participants with subthreshold Aβ levels at baseline. Plasma p-tau231 and GFAP did not provide any clear independent value.

Conclusions and relevance: Results of this cohort study suggest that combining plasma p-tau217and Aβ42/40 levels could be useful for predicting development of Aβ pathology in people with early stages of subthreshold Aβ accumulation. These biomarkers might thus facilitate screening of participants for future primary prevention trials.