A team of researchers have shown that a commercially-available blood biomarker test has comparable accuracy to cerebrospinal fluid (CSF) biomarkers in detecting Alzheimer’s disease pathology. The new research was published in JAMA Neurology on 22 January, and suggests that blood tests may be viable alternatives to more invasive lumbar punctures and CSF analyses, which are traditionally used to detect Alzheimer’s disease pathology. A well-established hallmark of Alzheimer’s disease is the presence of amyloid plaques in the brain. Current gold standard tests to detect amyloid involve PET scans or lumbar punctures, with analyses of the extracted CSF. However, these tests are both costly and invasive, and challenging to administer at scale in the community or primary care setting. In recent years, substantial efforts have been invested into the development and validation of blood-based biomarkers.
pTau217 is one of the leading candidate biomarkers, with several studies showing that the levels of pTau217 in the blood is significantly increased in people with AD. In the new JAMA Neurology paper, researchers aimed to determine the utility of a commercially available blood test for pTau217 for detecting AD pathology across different populations. The cohort study examined data from three clinical research studies: the TRIAD and WRAP US-based cohorts, and the SPIN cohort which is based in Spain. Each cohort involves participants with and without cognitive impairment, with data on their amyloid and tau status measured by the gold-standard PET and CSF tests.
In total, the research team (led by Henrik Zetterberg and Nicholas Ashton from the University of Gothenburg in Sweden) evaluated data from 786 participants, comparing the accuracy of pTau217 blood test results to the results of CSF tests, using PET scan results to categorise the amyloid positivity of participants. The pTau217 tests proved highly accurate in identifying people with elevated amyloid beta and tau levels in the brain, measured using PET scans. The accuracy of the pTau217 test was comparable to that of the CSF biomarker tests, validated across the three cohorts. Looking longitudinally, pTau217 values showed an annual increase only in individuals with amyloid beta positivity on their PET scans, further validating its utility even in the earlier, mild cognitive impairment stages of AD.
https://jamanetwork.com/journals/jamaneurology/fullarticle/2813751
