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Medical Daily

Elena Vega

New FDA-Approved Blood Tests Can Detect Alzheimer's Before Symptoms Worsen, but Access Remains Limited

FDA Medicare Disease Alzheimer Disease the Alzheimer Association Brain Dementia Johns Hopkins Medicine Memory

For decades, diagnosing Alzheimer's disease with certainty required either a spinal tap or a PET scan — procedures that are invasive, expensive, and often unavailable outside of major medical centers. That has changed.

The FDA approved the first blood-based test for Alzheimer's-linked brain changes in May 2025. A second test was cleared for use in primary care settings in October 2025. Taken together, these tests offer the possibility of earlier, more accessible, and far less costly identification of the amyloid plaques that are the hallmark of Alzheimer's disease.

But early detection is only valuable if people can actually access it. A new cost analysis from the University of Southern California estimates that the United States spent $781 billion on dementia in 2025. Researchers warn that those costs will keep rising unless early detection is deployed more equitably, which will require Medicare coverage, physician education, and rural access infrastructure that does not yet exist.

Why This Matters

Alzheimer's is now the leading cause of death in adults over 50 in the United States. Earlier diagnosis matters not just for peace of mind — it matters because new disease-modifying therapies like Leqembi and Kisunla, which are FDA-approved to slow disease progression, are only effective if started early, before widespread brain damage has occurred.

"New medications are now available to treat Alzheimer's disease, but they are only effective if it is diagnosed early, and early diagnosis depends on having accurate biomarkers," said Dr. Abhay Moghekar, an associate professor of neurology at the Johns Hopkins University School of Medicine, who helped validate the first approved test. "Getting a blood test is going to be far easier, quicker, and cheaper. It's going to allow early access to therapy, so it is going to revolutionize care of patients with dementia."

What We Know So Far

The first FDA-approved test — the Lumipulse G pTau217/ß-Amyloid 1-42 Plasma Ratio, made by Fujirebio Diagnostics — measures two proteins in the blood that are associated with amyloid plaque accumulation in the brain. According to Johns Hopkins Medicine, patients who score above the high-end cutoff have more than a 90 percent probability of having amyloid plaque in their brain. The test was granted FDA Breakthrough Device designation, reflecting its potential impact.

In a clinical validation study, 91.7 percent of individuals with a positive result had amyloid plaque confirmed by a follow-up PET scan or spinal fluid test. And 97.3 percent of those with a negative result were cleared through further investigation.

Both approved tests are currently authorized for use in patients 55 and older who are already experiencing memory problems or other signs of cognitive decline. They are not yet approved for screening of asymptomatic adults, which is the population where the greatest early intervention benefit could be realized.

The Access Gap

Despite the FDA approval, a major barrier remains: Medicare does not cover Alzheimer's blood tests for pre-symptom screening. Federal law allows Medicare to cover preventive services only when specifically authorized by Congress or recommended by the U.S. Preventive Services Task Force. The blood test does not yet meet that threshold.

"It is going to take an act of Congress," said Joe Grogan, former director of the Domestic Policy Council and a researcher at the USC Schaefer Institute, speaking at a June 2026 policy event on Alzheimer's costs, according to AHCJ Health Journalism.

The Alzheimer's Smart and Accelerated Prioritization (ASAP) Act, which would allow Medicare to cover biomarker testing before symptoms are severe, is pending in Congress but has not passed as of mid-2026.

Even for symptomatic patients who do qualify for the test, the financial picture is complicated. The anticipated out-of-pocket cost is $500 to $1,000, according to ALZRA — significantly less than a PET scan, which can cost several thousand dollars, but still a barrier for Medicare enrollees on fixed incomes if coverage is incomplete.

Where the Access Gaps Are Largest

The tests are currently being rolled out and becoming more widely available. However, geography remains a significant obstacle.

Rural communities, which often lack neurologists and geriatric psychiatrists entirely, face the steepest access challenge. The blood test's primary clinical value for primary care — where most older adults are seen first — requires physicians who are trained to interpret results, discuss implications, and manage referrals for further evaluation and treatment. That educational infrastructure does not yet exist uniformly.

Additionally, not every patient will have a clear positive or negative result. Approximately 20 percent of those tested fall in an intermediate category requiring additional testing from neurologists or gerontologists, supported by PET scans or cerebrospinal fluid testing — resources concentrated in academic medical centers in major cities.

What Doctors and Experts Say

"The FDA approval of a noninvasive blood test that can be more readily available and cost-effective is a giant step forward in the ability to help diagnose Alzheimer's disease earlier," said Ken Zaentz, president and CEO of Alzheimer's New Jersey. "This is especially significant when we now have disease-modifying treatments like Leqembi and Kisunla that have been shown to improve cognition in those with MCI and early-stage Alzheimer's disease."

Zaentz cautioned, however, that the test is not a standalone diagnostic tool. "The blood test is not meant to be a standalone test and it is not approved for use unless the individual has symptoms of cognitive impairment."

The Alzheimer's Association and major dementia researchers have supported expanding the test's use as part of a physician-guided diagnostic workup — while urging that results always be interpreted in the context of a full clinical evaluation.

What the Evidence Shows — and What It Does Not

MedicalDaily Evidence Check

Test name: Lumipulse G pTau217/ß-Amyloid 1-42 Plasma Ratio (Fujirebio Diagnostics)
FDA status: Approved May 2025; second test cleared for primary care, October 2025
Who it is for: Adults 55 and older with signs or symptoms of cognitive decline
What it detects: Amyloid plaques in the brain, a key Alzheimer's biomarker
Accuracy: 91.7% of positive results confirmed amyloid by PET or CSF; 97.3% of negative results also cleared
What it does not do: Provide a standalone diagnosis; not approved for asymptomatic screening; does not determine disease stage or rate of progression
Cost: Estimated $500–$1,000 (less than PET scan or spinal tap); Medicare coverage incomplete

Who Faces the Greatest Risk Without Better Access?

Adults over 65, particularly those with a family history of Alzheimer's, who live in rural areas or are on Medicare without supplemental insurance face the greatest barrier to accessing these tests. Without access, they will continue to receive diagnoses later in disease progression — when available treatments are less effective and caregiving and institutional costs are highest.

What You Can Do Now

If you are 55 or older and experiencing memory concerns, discuss Alzheimer's biomarker blood testing with your primary care physician or neurologist as part of a formal cognitive evaluation.
Ask your physician whether the Lumipulse test or the second cleared test is available at your local hospital or laboratory — rollout is ongoing but uneven.
If you are considering diagnostic testing, ask about insurance coverage and anticipated out-of-pocket costs before proceeding.
Do not use direct-to-consumer memory tests or unapproved online screens as a substitute for clinical evaluation — they cannot diagnose Alzheimer's disease.
Monitor federal legislation through the Alzheimer's Association for updates on Medicare coverage expansion.

Cost and Access: What Patients Should Know

The anticipated out-of-pocket cost for the Lumipulse test is $500 to $1,000 — substantially less than a PET scan, which typically costs $3,000 to $6,000. Medicare coverage for the test in symptomatic patients is expected as insurance coverage expands, but pre-symptom screening is not currently covered.

The National Institute on Aging and the Alzheimer's Association maintain hotlines and local chapter resources. Alzheimer's New Jersey's helpline is 888-280-6055.

What Happens Next

Congressional action on the ASAP Act would be the most significant near-term development for access expansion. Meanwhile, the rollout of the approved tests continues, with physician education programs expected to expand through 2026 and 2027. The USC dementia cost model will be updated as early detection and treatment penetration data improve. MedicalDaily will report on any Medicare coverage decisions or significant access expansions.

The Bottom Line

FDA-approved blood tests for early Alzheimer's detection are real and available today, for adults over 55 with cognitive symptoms. They are more accessible, less invasive, and less expensive than PET scans or spinal taps. But the pathway from approval to broad clinical use is not automatic — it requires Medicare coverage expansion, physician education, and rural care infrastructure that is still catching up. If you have concerns about memory changes, talk to your doctor now. Do not wait for the system to catch up.