New blood tests may help diagnose Alzheimer’s disease faster and more accurately

Alzheimer’s disease affects more than 6 million Americans and is the leading cause of dementia, but it can be challenging to correctly diagnose. Results of a new study suggest that a simple blood test may be able to quickly and accurately improve Alzheimer’s diagnosis. Private Health Management (PHM) is committed to providing our clients with Alzheimer’s with the most advanced care and we have helped them receive this useful test. Here are key takeaways from this promising study.

Study shows blood-based Alzheimer’s test is highly accurate
Traditional Alzheimer’s diagnosis relies on having a doctor review the patient’s symptoms and perform cognitive exams. Additional tools include brain scans, which are expensive and may take months to get, and spinal taps, which are invasive and can be uncomfortable.¹ Currently, several blood tests that can detect signs of Alzheimer’s are available, but they are not widely used due to high variability in their accuracy, limited guidance on which tests to use and when to use them, lack of FDA-approval, and challenges with insurance coverage.²

However, a recent study, published in the Journal of the American Medical Association and presented at the Alzheimer’s Association International Conference in July makes a strong case for utilizing a blood-based diagnostic called the amyloid probability score (APS2). The APS2 blood test, available in the U.S. as PrecivityAD2™, uses a statistical algorithm to analyze levels of two key proteins involved in Alzheimer’s disease, amyloid-beta (Aβ) and tau. Basically, the test analyzes the ratio of two forms of the tau protein (p-tau217/np-tau217) and compares it to a ratio of different forms of amyloid protein (Aβ42/40). Using these ratios, it calculates the probability that a patient has amyloid plaques in their brain, a primary marker of Alzheimer’s disease.³

The researchers examined data from 1200 patients in Sweden who had sought care for memory problems. About 300 patients were given the APS2 blood test and the results were compared with PET scans or spinal taps to confirm whether they had the disease. The study also had primary care doctors and memory specialists evaluate these patients to determine whether they had Alzheimer’s. Results showed that the APS2 blood test outperformed physician diagnosis, with 91% accuracy in identifying Alzheimer’s disease, while primary care doctors had a diagnostic accuracy of 61%, and specialists were 73% accurate.⁴ The blood test was more accurate in patients who had already developed symptoms than in patients with earlier stages of the disease.

This test may offer a promising option for diagnosing Alzheimer’s disease in patients who are developing symptoms or have a family history. Although there is no cure for Alzheimer’s, the FDA recently approved two new treatments, Leqembi (lecanemab) and Kisluna (donanemab). These treatments modestly slow worsening symptoms by targeting the amyloid plaques in the brain. The availability of an accurate, inexpensive, non-invasive diagnostic tool, like a blood test, could help more patients get diagnosed and treated when the disease is at relatively early stages.

PHM’s Personal Care Teams have been early adopters of innovative tests like PrecivityAD2, to help clients arrive at diagnoses quickly with more diagnostic clarity to expedite them on the right treatment plan. The positive results of this recent study further reinforce PHM’s leading edge approach to superior patient outcomes.

References

1. Porsteinsson, A. P., Isaacson, R. S., Knox, S., Sabbagh, M. N. & Rubino, I. Diagnosis of Early Alzheimer’s Disease: Clinical Practice in 2021. J Prev Alzheimers Dis 8, 371–386 (2021).
2. Farvadi, F., Hashemi, F., Amini, A., Alsadat Vakilinezhad, M. & Raee, M. J. Early Diagnosis of Alzheimer’s Disease with Blood Test; Tempting but Challenging. Int J Mol Cell Med 12, 172–210 (2023).
3. West, T. et al. A blood-based diagnostic test incorporating plasma Aβ42/40 ratio, ApoE proteotype, and age accurately identifies brain amyloid status: findings from a multi cohort validity analysis. Molecular Neurodegeneration 16, 30 (2021).
4. Palmqvist, S. et al. Blood Biomarkers to Detect Alzheimer Disease in Primary Care and Secondary Care. JAMA (2024) doi:10.1001/jama.2024.13855.