A study found that a simple blood test could detect the earliest signs of Alzheimer’s. This has “huge implications” in screening people over 50 to determine their risk of the disease.
Scientists from Sweden used a simple test kit, already available commercially to researchers. They found it could detect tau proteins that can cause Alzheimer’s disease and begin to accumulate on the brain up to 10 years before symptoms appear.
Experts said that it could be used by anyone of any age to test for the disease.
The test was used to determine whether people were likely to develop Alzheimer’s disease or not. If they fell in the middle, then more extensive testing would be required.
According to the study, the test is able to detect tau proteins up until 97 percent of the time.
Scientists have been able to detect tau protein in blood samples, which is linked to Alzheimer’s.
Bart De Strooper is a professor of Alzheimer’s research at University College London. He was not involved with the study by the scientists from the University of Gothenburg.
The study’s results were hailed as being particularly exciting, even when compared to other research studies that examined blood tests. This was due to the high accuracy, the large number of participants, and the fact that it used an existing testing kit, rather than one that needed custom-made.
The study also shows that , a blood-test can detect elevated tau levels as well as more invasive procedures like a spinal tap.
Sheona scales, director of research for Alzheimer’s Research UK said that the study suggested that measuring the levels of a p-tau217 protein in the blood may be as accurate as lumbar punctures, which are currently used to detect the biological signs of Alzheimer’s. It is also superior to other tests under development.
This study adds to the growing evidence that this test could revolutionise the diagnosis of people suspected to have Alzheimer’s.
David Curtis is an honorary professor of the UCL Genetics Institute who was not involved in this research. He said that when effective treatments are available to prevent Alzheimer’s progression, it will be important to be able identify those who are high-risk before they start to deteriorate.
“This study shows a simple blood-test could be used to measure levels of tau proteins in the blood… This could have potentially huge implications.”
Everybody over 50 should be screened regularly every few years in the same manner as they are screened now for high cholesterol. This could mean that the current treatments for Alzheimer’s would be more effective in those who are diagnosed earlier.
He said that the test should be “adopted as a standard test for blood, that could be done by a doctor on anyone who is concerned about dementia, even before referral to a clinic”, and that “NHS laboratoriescould perform it routinely”.
Curtis stated: “I’d expect it to be just as effective in younger people.” For routine population screening, one wouldn’t likely use it until around age 50 or 60.”
Scientists think the blood test will reduce the demand for more invasive ways to detect the disease.
The study, published in JAMA Neurology journal, examined 768 participants, with an average age 66. It compared the results of blood tests to those of cerebrospinal liquid taken via a spinal puncture. Researchers are investigating the possibility of collecting blood via finger prick in the future.
Scales stated: “What is particularly promising about this new study is that researchers used a threshold to divide people into three groups: those with Alzheimer’s disease who are very likely to develop the disease and those who do not. The ‘intermediate group’ would require further testing using conventional methods such as lumbar punctures, or PET scans.
Researchers predict that using a blood test this way could reduce the need for follow-up testing by 80 percent.
The study examined a test developed by ALZpath, a Californian company. The company hopes that its test will be available for clinical use by the first quarter of 2019. Before it could be used on UK patients, the test would need to receive regulatory approval.
If the test reveals that tau proteins have built up in the brain of the patient, they could be eligible for a variety of drugs and therapies under development that aim to slow down the progression of Alzheimer’s.
Once these drugs are available in clinical settings, they will be the most effective when used with a method of early diagnosis to delay the onset symptoms.
According to an estimate from 2019, there are approximately 900,000 Alzheimer’s patients in the UK. It is expected that this number will rise to 1.6 millions by 2040.
Nicholas Ashton said that the price of the test would be around $200 (£157) in the US. The Galleri cancer blood test, currently being tested on the NHS, costs $949 (£745).