New research reveals that highly accurate blood tests for Alzheimer’s can improve diagnosis accuracy and expedite treatment and research participation. These tests measure biomarkers like phosphorylated tau, which correlate with cognitive decline and brain atrophy.
Key Takeaways
- Blood tests for Alzheimer’s measure biomarkers like phosphorylated tau.
- These tests can significantly improve diagnostic accuracy and speed.
- Early identification through blood tests can expedite treatment and research participation.
Improved Diagnostic Accuracy
As highly accurate blood tests for Alzheimer’s disease are moving closer to use in physician’s offices, new research suggests that they may revolutionize the accuracy of diagnosis and provide a cleaner, quicker path to research participation and treatment. Dementia is often underdiagnosed, and many people are unaware or uninformed of their diagnosis. Blood tests for Alzheimer’s are demonstrating in research that they could significantly improve a clinician’s accuracy and confidence, provide greater accessibility, and enhance communication.
Promising Biomarkers
Blood tests that show the most promise for identifying Alzheimer’s-related changes in the brain assess phosphorylated tau (p-tau) protein, an Alzheimer’s biomarker that can build up before patients show signs of cognitive impairment. Increases in the specific marker p-tau217 over time correlate with worsening cognition and brain atrophy. The p-tau217 test also predicts the likelihood of amyloid plaques in the brain, which are another biomarker for Alzheimer’s and the target for recently approved treatments.
Clinical Implementation
“Blood tests, once they are confirmed in large populations to be more than 90% accurate and become more widely available, show promise for improving, and possibly redefining, the clinical trial recruitment process and the diagnostic work-up for Alzheimer’s,” said Maria C. Carrillo, Ph.D., Alzheimer’s Association chief science officer and medical affairs lead. While doctors in primary and secondary care should use a combination of cognitive and blood or other biomarker testing to diagnose Alzheimer’s, blood tests have the potential to increase the accuracy of early diagnoses and maximize the opportunity to access Alzheimer’s treatments as early as possible for better outcomes.
Study Findings
A large study reported at the Alzheimer’s Association International Conference® (AAIC®) 2024 shows that blood tests can do a better job of accurately detecting Alzheimer’s than both primary care doctors and specialists using traditional diagnostic methods. In the study, 1,213 patients were tested with the PrecivityAD2 test (known as “APS2”). It uses a combination of plasma phosphorylated-tau217 to not-phosphorylated-tau217 ratio (known as %p-tau217) and the ratio of two types of amyloid (Aβ42/Aβ40), and it significantly outperformed clinicians in this study.
- Among 698 patients seen at memory clinics, APS2 was around 90% accurate at identifying Alzheimer’s disease while specialists were 73% accurate.
- Among 515 patients seen in primary care, APS2 was also around 90% accurate; primary care physicians were 63% accurate at identifying Alzheimer’s.
Future Directions
Researchers observed that the APS2 test was highly accurate even in patients with comorbidities, such as kidney disease, which are common in older patients seen by primary care physicians. “These results were especially impressive considering that older populations in primary care often have medical conditions that can influence or vary the concentrations of p-tau217,” said lead author Sebastian Palmqvist, M.D., Ph.D., at Lund University, Sweden. The next steps include establishing clear guidelines for how an Alzheimer’s blood test can be used in clinical practice, preferably by implementing these tests first in specialist care and then in primary care.
Reducing Wait Times
Research reported at AAIC 2024 suggests that using high-performing blood tests in primary care could identify potential Alzheimer’s patients much earlier so specialists can determine if they are eligible for new treatments. The researchers used a well-established forecasting model to predict wait times for people eligible for treatment, accounting for both the limited number of Alzheimer’s disease specialists and the growing older population. The model suggests that by 2033, people will wait an average of nearly six years to understand if they could be eligible for new Alzheimer’s treatments if their primary care doctor only used brief cognitive assessments to make referrals. If blood tests were used to rule out Alzheimer’s, the average wait times would be reduced to 13 months for Alzheimer’s patients because far fewer patients would need to see a specialist.
Conclusion
“Our results suggest using blood tests to identify potential candidates for treatments could make a significant difference in treating people with early Alzheimer’s,” said Soeren Mattke, M.D., D.Sc., lead author of the study and director of the Brain Health Observatory, at the University of Southern California, Los Angeles. An easy-to-use blood test could help address the problem of lengthy wait times for diagnosis and treatment, ensuring that eligible patients receive timely care.
Sources
- Blood Tests Revolutionize Alzheimer’s Diagnosis – Neuroscience News, Neuroscience News.
