Blood Test May Spot Signs Of Early Alzheimer’s
By Robert Preidt HealthDay Reporter
THURSDAY, Aug. 1, 2019 — A simple blood test helped pinpoint the early signs of Alzheimer’s in a new study.
Up to two decades before people develop Alzheimer’s symptoms such as memory loss and confusion, harmful clumps of amyloid beta protein begin to accumulate in their brain, researchers explained.
But it’s possible to measure levels of amyloid beta in the blood and use that information to determine whether the protein has accumulated in the brain, they added.
Combining blood amyloid levels with two other major Alzheimer’s risk factors — age and the genetic variant APOE4 — can identify people who have early Alzheimer’s brain changes with 94% accuracy, according to the scientists from Washington University School of Medicine in St. Louis.
The study included 150 adults over age 50 who had no thinking or memory problems.
The blood test may be even more sensitive than the current gold standard — a PET brain scan — at detecting early amyloid accumulation in the brain, according to the authors.
The findings advance efforts to have a blood test to identify people who will develop Alzheimer’s before they have symptoms, and such a test could be available in doctors’ offices within a few years, the researchers said.
They added that the benefits of the blood test would be even greater once there are treatments to stop the progress of Alzheimer’s disease.
The study was published Aug. 1 in the journal Neurology.
Can Smelling Peanut Butter Detect Alzheimers
The peanut butter test is not how Alzheimers is diagnosed. Most Alzheimers patients do not lose their sense of smell but some do. The loss of sense of smell is called anosmia.
The problem with the peanut butter test is that Parkinsons disease patients can lose their sense of smell too. So, failing the peanut butter test doesnt mean you have Alzheimers disease. COVID or another viral infection could be hurting your sense of smell and could cause you to fail the peanut butter test. And thats temporary.
Its an interesting idea that has roots in some of the symptoms of the disease but its not accurate enough to replace standardized testing.
What Have Previous Tests And Treatments Looked Like And Why Have They Been Unsuccessful
Paulson: The cerebrospinal fluid measurements are actually quite good at helping doctors make the diagnosis of Alzheimers versus another dementia, but the ordeal of undergoing a procedure that many patients are not eager to undergo means that cerebrospinal fluid measurements are not routinely used in clinical practice.
PET imaging of amyloid and tau is remarkably powerful, but, in the current absence of insurance coverage, most patients simply cannot afford it. Thus, for now, it remains a research test.
Treatments are another matter altogether. While anti-amyloid therapies continue to be tested, they have not been robustly positive in clinical trials. We dont yet know if that lack of effectiveness is due, perhaps, to giving the treatments too late or due to anti-amyloid treatments simply being insufficient as a therapy for Alzheimers.
A simple and sensitive blood test that could pinpoint the Alzheimers disease process well before any cognitive symptoms would allow us to give any potential disease-slowing therapy anti-amyloid, anti-tau, anti-inflammatory at a very early point in the disease process. Doing so likely will increase our chances of finding an effective therapy.
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Could You Begin With Self
Yes, you may start with a self-assessment test. Many people who have memory loss concerns might want to start there.
Even though this is very hard for all humans to do, its best to listen to your friends and family members who might be recognizing things about your memory that you dont.
If they are expressing concerns about your memory. thats probably a good indication to get it professionally checked by a geriatrician, neurologist or a mental health professional.
Qplextm Alz Plus Assay
Quantamatrixs multiplex diagnostics platform was applied as previously described for the QPLEXTM kit with microdisk technology to analyze multiplexes in a single well. This system utilizes graphically coded beads that can expose antigens. In brief, diluted human plasma samples were incubated with the coded beads and antibodies in a 96-well plate. A 96-well plate was incubated in a shaking incubator at 1000rpm for 90min at RT. Coded beads, including immunocomplexes, were washed on a Biotek-510 magnetic wash station . Fifty microliters of diluted R-phycoerythrin-conjugated streptavidin were added to each well and incubated for 15min at RT. After incubation, the immunocomplexes were washed three times. Complexes were resuspended in 100l of washing buffer and analyzed.
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Transformative Step To Earlier Diagnosis
Speaking of the results, Professor Masud Husain from the University of Oxford said: This is a potential game-changer.
For the first time, we have a blood test that can predict well the risk of subsequent development of Alzheimers disease in people who have mild cognitive symptoms.
We need further validation but in the context of other recent findings this could be a transformative step to earlier diagnosis, as well as testing new treatments at earlier stages of the disease.
Diagnosing Alzheimers: Biomarker Tests
These are tests that look at what we call biomarkers. Biomarkers are biological chemicals or changes that are known to indicate disease. In this case we look for biomarkers of Alzheimers disease.
There are two main biomarker tests: the positron emission tomography or PET scan and the body fluids test .
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Alzheimers Blood Tests Show New Promise Giving Decades Of Early Warning
A new blood test for Alzheimers disease has shown it can be just as accurate or better than the current standards for diagnosis, performing nearly on par with potentially expensive PET brain scans and invasive spinal taps for cerebrospinal fluid.
Presented at the Alzheimers Association International Conference, multiple researchers debuted studies demonstrating how certain proteins found in the bloodstream could warn of the neurodegenerative diseaseincluding up to two decades before any outward signs of dementia.
One particular form of the tau protein, which clusters together to create tangles within neurons and causes the cellular malfunctions that lead to Alzheimers and cognitive decline, was found to be the one of the earliest to show changes. Known as p-tau217, the proteins levels also appeared to correlate with amyloid proteins, which form the plaque deposits that can also interfere with brain function.
An international team of researchersincluding scientists from Lund University in Sweden and Banner Alzheimers Institute in the U.S., plus the drugmaker Eli Lilly and othersstudied more than 1,400 cases and a number of experimental biomarkers.
They found that p-tau217 was specific to Alzheimers and that blood tests were able to distinguish the disease from other neurodegenerative disorders 89% to 98% of the time.
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Currently, biomarkers brain changes and abnormal levels of certain proteins measured by scans and spinal taps can predict whether a person who has normal cognition now will go on to develop Alzheimers. But these tests are invasive, expensive and time-consuming.
The appeal of the eye test is that it could perhaps give patients and doctors similar information, but inexpensively, within minutes and without the need for needles, anesthesia or recovery time, Van Stavern said.
Theres already a large body of literature showing structural changes in the retina and the optic nerve in patients with established Alzheimers disease, he noted. That tells tells researchers the pathologic changes in the brain are parallel to some degree to the changes in the eye.
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Blood Tests Being Developed In Oslo
Tormod Fladby at OUS is also working on developing a blood test-based diagnostics.
We use immune cells in the blood, monocytes and macrophages, and see how these interact with Alzheimer’s-related proteins. We believe this will also be a simple and useful method, he said.
The reason why they and their colleagues in Sweden are making great progress now is that the technology for measuring small amounts of protein has become more advanced, he said.
A New Target And An Exciting Test Emerges
For years, efforts to find such an easily obtainable Alzheimers diagnostic biomarker in the blood came up empty they were not accurate enough.
A major reason for inconsistency of the prior reports was the extremely small amounts of these protein fragments in the blood. The tests have to be sensitive enough to detect either amyloid or tau, and be accurate enough that the blood level changes occurring in people with Alzheimers can be clearly different from those of non-affected people.
Now, several publications and presentations at the recent Alzheimers Association International Conference have demonstrated that blood tests measuring amyloid and tau proteins have become much more sensitive and accurate enough to allow their possible future use as routine aids in Alzheimers disease diagnosis.
These various tests are at different stages of validation assuring theyre accurate across many different patient populations. And, for each protein, there are several different methods for making the blood measurements. However, the research community is excited about the possibilities.
And one new tau blood test appears to meet a number of criteria necessary.
To be useful, the tests have to be nearly perfect predictors. Many arent there yet so far, they seem to get it right up to over 85% of the time. And the accuracy will be very important if theyre to be used to screen people for positive tests and enter those people into clinical trials.
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Alzheimer’s Blood Test Comes To The Clinic
Pauline Anderson
The first blood test to detect the presence of amyloid, a hallmark of Alzheimer’s disease , is now available for clinical use, the company behind the test’s development, C2N Diagnostics, has announced. The availability of the noninvasive, easily administered test is being called a milestone in the early detection and diagnosis of AD.
The blood test “introduces a new option for patients, families, and the medical community that have eagerly awaited innovative tools to address Alzheimer’s troubling problems,” Joel B. Braunstein, MD, CEO of C2N Diagnostics, said in a press release.
“This is really an important advance,” said Howard Fillit, MD, founding executive director and chief science officer of the Alzheimer’s Drug Discovery Foundation , which partially funded the development of the test, in a separate press release.
“You can now walk into your doctor’s office to get a blood test to help detect Alzheimer’s disease,” said Fillit. “This test answers a critical need for less costly and accessible diagnostic testing in memory and dementia care.”
When Should I Go To My Gp To Have My Memory Tested
You should visit your GP if problems with your memory have started to have an impact on your life. This might mean that you are struggling to do your job or having difficulty with everyday living or you are regularly forgetting where you are supposed to be, or are becoming increasingly muddled with things that used to be easy for you to do.
If you witness these symptoms in someone else you know, you could encourage them to visit their GP.
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The Brain Scan: Does Alzheimers Show Up On An Mri
Brain scans or brain imaging are typically done with special agents. These special chemicals are injected into the bloodstream, travel to the brain and light up the beta amyloid plaques.
This type of imaging is called PET imaging or PET scan. Its very specific to Alzheimers disease plaque pathology because of the slightly radioactive agents that are injected. Once the agents reach the brain, the patient slides into a brain scanner where the amount of Alzheimers plaque you have in your brain can be seen and measured.
Tests designed to light up tau tangles, the other hallmark of Alzheimers disease, are in development.
PET scans are good but also not 100% accurate, With a memory test alone we might be 80% to 90% accurate. A PET scan will increase the accuracy level,
After that, many physicians, if they have access to the technology, will order a secondary biomarker test. And with the additional biomarker test the accuracy can improve further.
Elevated Levels Detected Long Before Symptoms Appeared
The disease is a consequence of high levels of amyloid and tau proteins in the brain.
The researchers took blood samples from 1,100 Swedish inhabitants over a number of years. They used their test to measure the presence of phosphorylated tau protein .
They then compared these blood tests with individuals who were subsequently diagnosed with Alzheimer’s.
The test revealed a strong link between elevated levels of this specific tau protein in the blood and the loss of nerve cells and impaired cognitive ability in Alzheimer’s disease several years later.
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Physical & Neurological Exam
A specialist may administer physical or neurological exams to rule out certain conditions. Unfortunately, there is not a single diagnostic test that can diagnose Alzheimers, so doctors rely on other tests to rule out any other condition that could explain the dementia-like symptoms.
Administering physical exams when you suspect Alzheimers disease is largely used to rule out other conditions that could be causing your dementia symptoms. These dementia-like symptoms may be caused by depression, untreated sleep apnea, side effects of pharmaceuticals, or certain vitamin deficiencies.
Physical exams for diagnosing Alzheimers disease may include:
- Measuring blood pressure, temperature, and pulse
- Monitoring heart and lungs for abnormalities
- Collecting blood samples or urine samples for lab testing
- Reviewing what medications youre taking
- Talking about your sleep habits
- Going through your diet, nutrition, and alcohol consumption
With a neurological exam, doctors can rule out neurological conditions that could be causing your dementia-like symptoms. These conditions may include tumors, fluid accumulation on the brain, Parkinsons, or strokes large and small.
Neurological exams for diagnosing Alzheimers may include:
- Testing reflexes
- Brain imaging
Who Administers All These Neuropsychological Tests
To get an Alzheimers diagnosis typically you see a specialist, like a neurologist. A neurologist may not administer all of these tests directly but he or she will interpret the cognitive test results with help from specialized colleagues.
Neurologists have special team members who administer the memory and thinking or cognitive tests. They have another team who are specialists at doing the PET imaging and interpretation of the brain scan results. And they rely on clinical laboratories to do the blood and cerebral spinal fluid testing.
Typically, the neurologist leads and coordinates these specialized teams and will interpret your test results together with your medical history to reach a diagnosis.
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How Is Alzheimers Diagnosed
Alzheimers is diagnosed by going through a medical history, ruling out other possible causes that could explain your dementia-like symptoms, administering imaging tests, and looking for biomarkers that indicate the progression of Alzheimers.
Alzheimers disease is a serious neurodegenerative condition that is the result of chronic inflammation that leads to tau tangles and beta-amyloid plaque buildup in the brain. This progresses to mild cognitive impairment, then more serious dementia symptoms, such as memory loss and decreasing mobility.
The National Institute on Aging points out that Alzheimers is the sixth-leading cause of death in the US, but the third leading cause of death in older Americans. In Japan and the UK, its the #1 cause of death.
According to the Alzheimers Association, an estimated 1 in 10 older adults have Alzheimers disease. 1 in 3 Americans over the age of 85 have Alzheimers dementia.
Diagnosing Alzheimers can be done by a neurologist, a neuropsychologist, a geriatrician, or even your primary doctor if they have prior experience with diagnosing types of dementia.
Alzheimers cannot be truly diagnosed until after death by meticulously examining brain tissue in an autopsy.
However, there are biomarkers and helpful indications that aid physicians in diagnosing Alzheimers disease to the best of their ability, such as amyloid particles in blood plasma or cerebrospinal fluid.
See The Hunt For A Blood Test For Alzheimers Disease
The C2N test relies on the ratio of two isoforms of the amyloid- protein, A42 and A40, that aggregate to form amyloid plaques in the brain, combined with the presence of isoforms of apolipoprotein E that reflect whether the patient caries a genetic variant associated with Alzheimers risk. The results are combined into a score that indicates the probability that a patient would be found to have amyloid plaques if they were to undergo an amyloid PET scan. Doctors can then consider the test results along with other information about the patient to arrive at a diagnosis. According to data posted on the companys website, a study in 686 patients with cognitive impairment found that those with scores above a certain cutoff point had a positive amyloid PET scan 92 percent of the time, while those with scores below a certain cutoff had a 77 percent chance of having a negative result on the PET scan.
While no drugs have yet been approved to treat Alzheimers, being able to distinguish it from other possible causes of cognitive impairment is nonetheless valuable, Fillit and Schindler say. As a clinician, Schindler says, I want to know what my patients have. That can be complicated because in many cases, they dont just have memory impairment, theyre taking multiple medications, they have all sorts of health issues, she says. And sometimes its really hard to know whether the symptoms theyre experiencing are due to something like Alzheimers or something else.
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Alzheimers Blood Tests Available In The Future
Another test thats shown promise is called the Simoa that also tests for proteins in blood plasma. Its the same idea as other blood tests: identify biomarkers in the blood that can usually only be seen via expensive or difficult exams including PET brain scans, MRIs, and spinal taps. The specific protein Simoa can detect is called ptau181, and has been linked to the changes caused by dementia in the brain.
In studies, the Simoa was found to be as good at predicting the development of dementia as PET scans and a spinal tap, without the cost, pain, or radioactivity associated with those tests. And the test can also detect upcoming dementia-caused brain changes in both the short and longer terms. Right now, this technology is used by researchers to identify people who are good candidates for clinical trials. It is not yet available for most patients.