A new blood test called APS2 (the amyloid probability score 2) has recently been found to be more accurate than doctors in diagnosing Alzheimer’s disease in people with early-stage illness. The test has a 91% accuracy rate as compared to the 61% success rate of doctors.
Dr. Teresa D’Amato said that this blood test is accurate and can be used as a first round of diagnostic testing and considered it very exciting. But the test is not yet approved for routine use.
The findings were recently published in the Journal of the American Medical Association and simultaneously presented at the Alzheimer’s Association International Conference in Philadelphia.
This new diagnostic test was developed by Dr. Sebastian Palmquist from Skane University Hospital and Lund University in Sweden. This test is expected to be cost-effective for doctors’ offices and can also be approved by the FDA soon.
This test measures the levels of two proteins in the blood such as Tau and amyloid. Researchers involved 1,213 patients with cognitive symptoms to check the effectiveness and accuracy of this test. These patients were aged around 74 years old.
Researchers found that 23% of the participants experienced subjective cognitive decline, 44% had mild cognitive impairment, and 33% had been diagnosed with dementia.
Primary care physicians assessed patients using standard criteria, cognitive tests CT scans. Patients also received the APS2 blood test. The results of these tests were compared to “gold standard” Alzheimer’s tests like cerebrospinal fluid tests and PET scans.
When researchers observed the results, they found that ASPS2 was 91% accurate in detecting Alzheimer’s disease. On the other hand, the accuracy of primary care doctors was 61%.
The test accurately measured the tau protein. It was found to be the most important for diagnosing Alzheimer’s disease alone with a 90% accuracy rate.
The authors believe that the ASPS2 test can be an effective way to diagnose Alzheimer’s earlier if healthcare professionals use it correctly. But they also warn that this blood test alone cannot diagnose Alzheimer’s early in its development because symptoms can also be caused by other conditions. Hence, incorrect interpretation of the test can increase the risk of underdiagnosis of non-Alzheimer disease conditions.
Reference Link:
Sebastian Palmqvist et al, Blood Biomarkers to Detect Alzheimer Disease in Primary Care and Secondary Care, JAMA (2024). DOI: 10.1001/jama.2024.13855
Stephen Salloway et al, Are Blood Tests for Alzheimer Disease Ready for Prime Time?, JAMA (2024). DOI: 10.1001/jama.2024.12814
