While Alzheimer’s disease was first discovered in 1906, it wasn’t until 1984 that the amyloid-β peptide was identified as the main substance making up the brain plaques that are the hallmark of the disease.
Today, there are various therapies to treat Alzheimer’s symptoms and even some promising therapies for slowing it down. While there’s still no cure, researchers have recently made some groundbreaking progress that can aid in diagnosis. The first blood test for Alzheimer’s early detection, Lumipulse G pTau217/ß-Amyloid 1-42 Plasma Ratio, has been approved by the Food and Drug Administration (FDA).
The blood test for Alzheimer’s is still relatively new, but members of the Sermo community are already sharing firsthand experiences with diagnostic tests and resolving questions as they arise.
Is Alzheimer’s disease on the rise?
Currently, more than seven million Americans have Alzheimer’s disease, according to a report from the Alzheimer’s Association. Women are more likely to develop Alzheimer’s, with their lifetime risk by age 45 being 20 percent as compared to 10 percent in men, according to the report.
For Americans over 65, Alzheimer’s was the sixth leading cause of death in 2022. Deaths from Alzheimer’s exceed those from breast and prostate cancer combined. While deaths from stroke, heart disease and HIV decreased between 2000 to 2021, Alzheimer’s disease deaths actually rose by over 140% in the same time span.
In a poll of the doctors in the Sermo community, 46% said they’ve noticed a moderate increase in Alzheimer’s in their community, 26% said they’ve noticed a significant increase, and 20% a slight increase.
What tests have traditionally been used to diagnose Alzheimer’s?
There isn’t one singular test that physicians can use to diagnose a person with Alzheimer’s. A diagnosis requires a more multimodal approach.
Simple, non-invasive tests
In diagnosing Alzheimer’s, doctors often consider family history, symptoms and risk factors. They also do a physical and neurological exam to determine if the patient presents with any symptoms that suggest a different brain condition.
Cognitive, functional and behavioral tests can assess the patient’s mental status and whether they’re experiencing memory loss, critical thinking and problem-solving deficits and other key Alzheimer’s indicators. The FDA has cleared several digital tests for detecting cognitive impairment, such as Cognivue Clarity and Thrive and CognICA Integrated Cognitive Assessment.
In a small sample poll of Sermo members asking how they diagnose Alzheimer’s, the most common answers were cognitive and functional evaluations (26%) and medical history (23%).
Brain scans
18% of polled Sermo members said they use brain imaging in diagnosing Alzheimer’s. Physicians can use an MRI or CT scan to detect any structural issues that could rule out Alzheimer’s as the cause of the patient’s symptoms. They can also use PET scans to detect amyloid plaques.
Lumbar Puncture
Physicians may also opt for more invasive testing. They may perform a lumbar puncture (LP) so that they can collect cerebrospinal fluid (CSF) to check Alzheimer’s biomarkers such as high tau and low beta-amyloid levels. The FDA has approved two assays for measuring both biomarkers in CSF.
The Lumipulse G pTau217/ß-Amyloid 1-42 Plasma Ratio Test
Physicians now have a new tool in their Alzheimer’s diagnosis toolbox. Fujirebio’s Lumipulse G pTau217/ß-Amyloid 1-42 Plasma Ratio is the first FDA-cleared Alzheimer’s blood test. It’s a development that many Sermo members are excited about; in a poll, 59% said they “strongly agree” that the test is important as it can speed up diagnosis, and 25% “agree.”
The test uses the same principle as CSF Alzheimer testing, calculating the numerical ratio of two Alzheimer’s biomarkers, pTau217 and β-amyloid 1-42, found in human plasma. However, the new blood test is less invasive and painful than the CSF test.
Doctors are often rightfully cautious about ordering time-consuming tests like a PET scan or invasive and potentially dangerous tests like an LP unless the symptoms are very indicative of Alzheimer’s. However, by that point, the disease may be pretty advanced. When asked if they have patients who struggle to get an accurate Alzheimer’s diagnosis due to the complexity of testing, 43% of polled Sermo members said they’ve had some patients, and 27% said they’ve had many.
Now, physicians can order a blood test with little risk to the patient much sooner, leading to earlier Alzheimer’s detection. Since available treatments can slow rather than cure Alzheimer’s, early detection is crucial.Many physicians on Sermo have never used blood tests for Alzheimer’s diagnosis. A majority of polled Sermo members (59%) indicated that neither they nor their colleagues have.
Can blood tests really detect Alzheimer’s and other dementia?
As mentioned, Alzheimer’s disease is characterized by a buildup of two substances in the brain: The amyloid-β peptide, which causes the plaques on the brain, and the tau protein, which makes up the classic Alzheimer’s neurofibrillary tangles. The body naturally tries to remove this buildup and clear it out of the brain, and both get flushed into the CSF and bloodstream.
A blood test can quantify the amount of each in the blood to provide a ratio between them. A person with Alzheimer’s will have a higher p-Tau to β-amyloid 42 ratio in their blood. A blood test for Alzheimer’s isn’t definitive on its own, but neither are other Alzheimer’s diagnostic tools. And notably, one study found the Lumipulse test to be more accurate compared to two other types of blood tests for Alzheimer’s diagnosis. A blood test that’s accurate without the barriers of other forms of testing is a step in the right direction.
What doctors are saying about blood tests for Alzheimer’s
Many Sermo community members intend to use the new blood test. In a poll, 33% said they had many patients they’d recommend it to, 32% had some patients they’d recommend it to, and 14% would recommend it to at least a few of their patients.
Sermo members are interested to see how the technology could change Alzheimer’s diagnosis. “It would be a great advance to be able to diagnose Alzheimer’s in time, with a blood test that would be cost-effective in addition to a rapid test,ˮ writes a general practitioner. “It would be interesting to know how results of this test change with therapy,” a gastroenterologist adds.
However, not everyone’s fully convinced. While CSF testing and blood tests use the same mechanism, blood doesn’t contain as high of a concentration of the biomarkers. This makes the test less sensitive and less able to detect cases in patients who already have lower amounts of the biomarkers present.
The effect may be even more pronounced in some patients. One study highlighted that Black patients have lower concentrations of Alzheimer’s biomarkers in their CSF — and their blood — compared to white patients. Therefore, the study authors recommended exercising “extreme caution” using blood tests to diagnose Alzheimer’s in Black patients.
In a poll, 68% of Sermo members indicated that they have concerns about how the new blood test could be misinterpreted, and feel that healthcare professionals should understand it’s not a one-and-done test.
Some Sermo members have their doubts. “Would like to see this verified in more robust clinical trials first,” writes an internal medicine specialist. “Until we have a treatment that could be useful in the context of early diagnosis, this will do nothing but satisfy curiosity or tell us something we already know,” states a family medicine physician.
Key takeaways
Alzheimer’s cases are on the rise, based on national statistics and Sermo members’ anecdotal observations. The trend raises concerns about healthcare readiness and the need for faster, more accessible diagnostic tools, as traditional testing can be complex and invasive. These challenges can delay diagnosis and treatment.
The FDA-approved Lumipulse test offers an alternative way to detect Alzheimer’s through blood biomarkers. It can potentially speed up diagnosis, allowing patients to get help earlier when treatment is more effective.
Physicians on Sermo are actively discussing the new test, sharing experiences, expressing concerns and detailing how it fits into their clinical routines. Some of them view having a blood test for Alzheimer’s as a good thing. Early detection of Alzheimer’s is a priority, not only because treatment options slow rather than cure the condition, but because the tests may be more comfortable to patients. Having a minimally invasive Alzheimer’s test that can be done right in the doctor’s office or clinic may help speed up diagnosis.
Some members caution against treating blood tests as a one-and-done diagnostic tool, advocating for using blood tests in conjunction with patient history and cognitive and neurological evaluations.
Discussions around this medical technology will likely evolve over time. Sermo members engage in meaningful daily discussions on new breakthroughs like this one every day. Join the discourse to stay informed and help shape the future of medicine.
