According to a novel study, a blood test that combines cognitive decline detection and memory loss detection has an amazing 90% accuracy rate in identifying memory loss as a result of Alzheimer’s disease. Compared to primary care physicians, who had an even lower success rate of 61%, and neurologists and other memory specialists, who properly identified Alzheimer’s in 73% of their cases, this is a substantial advancement.

A part of the blood test in question is called plasma phosphorylated tau 217, or p-tau217. Scientists are examining a number of blood biomarkers, including this one, to see if it may be used to diagnose Alzheimer’s disease in its early stages and mild cognitive impairment. Dr. Sebastian Palmqvist, senior consultant neurologist and associate professor at Lund University in Sweden, states that tau protein 217, a reliable marker of amyloid disease, is measured by the test. According to Dr. Palmqvist, p-tau217 blood concentration rises are noticeably higher in Alzheimer’s disease patients. When comparing elderly people with Alzheimer’s to those in the dementia stage of the disease, levels of p-tau217 are more than eight times greater.
A similar p-tau217 test may be up to 96% accurate in detecting increased levels of beta-amyloid and up to 97% accurate in detecting tau, according to research published earlier this year. The brain’s beta-amyloid and tau tangles are characteristic indicators of Alzheimer’s disease. The p-tau217 test was used in the latest study in conjunction with the amyloid 42/40 ratio, another blood biomarker for Alzheimer’s disease. Two forms of amyloid proteins, which are also indicators of Alzheimer’s disease, are measured by this ratio. It was discovered that the amyloid likelihood score—a composite of these tests—was the most predictive.

The Alzheimer’s Association’s chief science officer, Dr. Maria Carrillo, was excited about the prospect of such a blood test, comparing its use to that of a cholesterol test for Alzheimer’s. She stated that the p-tau217 blood test is a leader in Alzheimer’s research since it seems to be the most valid and specific for the disease.

Once completely confirmed, highly accurate blood tests have the potential to transform the pace of Alzheimer’s clinical trials and expedite the discovery of novel drugs. Dr. Carrillo stressed that these advancements signify revolutionary periods in the study and management of Alzheimer’s disease.
The p-tau217 blood test has an interesting mechanism. Dr. Carrillo states that the presence of amyloid plaques in the brain is a prerequisite for the detection of the peptide p-tau217. She clarified that measuring p-tau217 enables researchers to identify tau-induced neuronal damage relatively early in the course of Alzheimer’s disease, but only in the presence of amyloid. Despite not measuring amyloid directly, the test can predict its presence based on objective PET (positron emission tomography) scans supporting the correlation.

Numerous other neurological conditions, including frontotemporal dementia (FTD), have been linked to tau tangles. Tau tangles in FTD mostly impact the frontal lobe of the brain, resulting in behavioral, affective, and executive function loss. On the other hand, tau tangles build up in the parts of the brain linked to memory in Alzheimer’s disease, and amyloid plaques are important. These plaques have the potential to cause inflammation that worsens brain injury and to obstruct synaptic connections between nerve cells.
Lecanemab and donanemab, two of the newest medications for dementia, target beta-amyloid and may be less effective in people with extensive tau disease. Since amyloid deposits can begin to build up in the brain decades before symptoms manifest, usually in the late 30s or early 40s, early detection may be essential for putting preventive measures and lifestyle modifications into action.

The study, which was written up in the journal JAMA Neurology, tracked 1,213 people who, on average, were 74 years old while they underwent cognitive assessments in Swedish main care and specialized clinics. A final diagnostic score was created by combining the results of the p-tau217 test on each participant’s blood with the beta-amyloid 40/42 measures. When compared to employing p-tau217 alone, this combined technique greatly increased the diagnostic accuracy.

A spinal fluid tap was used to validate the study’s 90% accuracy rate for the combined blood test. This procedure, coupled with an amyloid PET scan, is currently considered the gold standard for detecting Alzheimer’s disease. However, these tests are pricy, intrusive, and not available to everyone. The results of the blood test were also contrasted with the diagnoses made by Swedish specialists and primary care physicians, whose lower accuracy rates demonstrate the difficulties in detecting Alzheimer’s given the resources available today.

Alzheimer’s disease cannot always be diagnosed with high accuracy using typical cognitive evaluations, according to Dr. Oskar Hansson, a professor and senior consultant in neurology at Lund University. Many people who consult specialists may also have illnesses including vascular dementia, depression, thyroid disease, sleep apnea, or vitamin B12 deficiency that resemble the symptoms of Alzheimer’s disease. These imitators may make it more difficult to diagnose patients and cause delays in getting the right care for those who actually have Alzheimer’s disease.
Accurate diagnostic instruments will become more and more necessary as the population ages. Without better diagnostic techniques, mathematical models predict that by 2033 people may have to wait an average of almost six years to learn if they qualify for new Alzheimer’s therapies. On the other hand, this waiting period might be cut to six to thirteen months with the use of precise blood testing, greatly increasing patient outcomes.

There are currently no standard blood testing for Alzheimer’s available in primary care settings, despite the encouraging results. To confirm these results, make recommendations for physician use, and inform healthcare professionals on the subtleties of these tests, more study is required. The director of research at the Institute for Neurodegenerative Diseases in Florida, Dr. Richard Isaacson, stressed the significance of following up on good blood test findings with additional testing such as spinal taps or PET scans.

People can prevent or delay cognitive decline in the interim by implementing a number of evidence-based therapies, such as consistent exercise, a Mediterranean-style diet, and controlling vascular risk factors like high blood pressure, high cholesterol, and diabetes. There is promise for better early detection and management of Alzheimer’s disease because to these tactics and improvements in diagnostic testing.