New research released this week reveals that a simple blood test can outperform traditional exams to diagnose Alzheimer’s. However, where and when to get a blood test can be tricky in Florida.
Labs throughout Florida, such as Quest and Labcorp, already offer tests that can detect certain signs of Alzheimer’s in blood. You can get one if you have a doctor’s order and money to pay for the test, which can cost from $200 to $500. The U.S. Food and Drug Administration has not approved the blood tests for Alzheimer’s diagnosis, and because of that, there is no insurance coverage.
If you choose to get a blood test under a doctor’s supervision, you will want to consider that not all blood tests for Alzheimer’s are the same. The test that shows the most promise for identifying Alzheimer’s-related changes in the brain looks at two biomarkers — the level of p-tau217, a type of protein that builds up in the brain in Alzheimer’s patients, and amyloid beta, another protein that gradually builds up into plaques.
A new study of 1,200 patients presented Sunday at the Alzheimer’s Association International Conference revealed that the test for the p-tau21 protein accurately diagnosed the disease about 90% of the time in people having memory problems. Compare that with dementia specialists who successfully identified Alzheimer’s 73% of the time and primary care doctors who did so with a 63% rate. The test used in the study is made by St. Louis-based C2N Diagnostics. The list price is $1,450.
Experts equate the potential for using a blood test to detect biomarkers for Alzheimer’s to measuring cholesterol levels to help detect heart disease.
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The study researchers concluded that having the simple test at their disposal would help doctors and specialists who rely on symptoms for a diagnosis.
“For now, Floridians cannot go to primary care and expect blood tests will be used to ensure they do or don’t have the disease,” said Stefanie Wardlow, senior program manager and research champion at the Alzheimer’s Association Florida Chapter. “All the data is not in yet.”
Wardlow said blood tests still need to be confirmed in large populations and become more widely available.
“The field is moving so quickly it feels like we should be there, but we don’t know yet if it’s appropriate for all populations,” Wardlow said.
An estimated 580,000 Floridians ages 65 and older are living with Alzheimer’s disease, the second-highest prevalence in the country and the highest per capita. Those figures, provided by the Alzheimer’s Association, are current as of July 2023. Test manufacturers will be conducting clinical trials for the blood tests on a larger and more diverse group of test subjects, and Floridians may be able to participate. Check clinicaltrials.gov to learn more.
Floridians who seek a confirmed diagnosis must undergo more expensive and invasive FDA-approved tests. Those are PET scans, which can cost $5,000 or more, and spinal taps, which can be invasive and costly. As of Jan. 1, 2025, Florida law requires Medicaid and state employee health insurance plans to cover the two FDA-approved tests for Alzheimer’s.
Researchers believe that blood tests eventually will replace the PET scan and spinal tap to diagnose the disease, particularly when time is critical to slowing progression. Wait times for these tests and the specialists who read them can be lengthy. Those diagnosed with Alzheimer’s typically seek to begin treatment immediately after a diagnosis to keep their quality of life as long as possible. A diagnosis also provides an opportunity to enroll in clinical trials for treatments.
“The blood test is really going to change the clinician’s ability to detect and make an accurate Alzheimer’s diagnosis, and it’s going to have treatment implications down the road,” said Dr. James Galvin, founder and director of the Comprehensive Center for Brain at University of Miami Health System. Galvin said the blood test should not be given to people who don’t have symptoms and should not be given if the doctor does not think Alzheimer’s is a possibility.
“If the average person wants to know their risk, this is not the test,” he said.
Galvin expressed hope about new treatments that can stop or delay the progression of Alzheimer’s.
Drug manufacturers are presenting early-stage research findings on oral medications at the Alzheimer’s Association International Conference this week. In research findings presented Tuesday at the conference, a small study of weight-loss drugs similar to Ozempic tied the medication to a slowdown in cognitive decline in people with mild Alzheimer’s disease. The results need to be borne out in larger trials before the medicines could receive approval for the disease.
Researchers also are studying various drugs used for other health conditions such as diabetes, heart disease, and menopause to learn whether they slow, stop, or even reverse memory loss.
Already, the FDA has approved two medications for people with mild Alzheimer’s disease — lecanemab (Leqembi) given as an infusion every two weeks, and the newly approved donanemab (Kisunla) given as an infusion every four weeks. Clinical trials found that the monoclonal antibody infusions slowed declines in thinking and functioning in people with early Alzheimer’s disease. They do have the potential for side effects, though. Those include infusion-related reactions such as nausea and vomiting, as well as the potential for swelling or small bleeds in the brain.
Galvin and other experts believe that because Alzheimer’s is a complex disease, the most effective treatments in the future may include a combination of medicines.
Sun Sentinel health reporter Cindy Goodman can be reached at cgoodman@sunsentinel.com.
