Tauklarify is a new PET imaging tracer that lets doctors see tau tangles in the brain, and its approval gives clinicians a second tau-imaging option alongside the amyloid scans already used to diagnose Alzheimer's disease. The FDA cleared it on August 14, 2026 for adults with cognitive impairment being evaluated for Alzheimer's, but it does not replace amyloid PET or change how most people with mild cognitive impairment (MCI) get diagnosed or qualify for treatment, according to Healio's report on the Lantheus approval. For someone newly diagnosed with MCI, the practical takeaway is narrower than it sounds: Tauklarify adds detail about tau pathology that can help confirm an Alzheimer's-type process and gauge how far it has progressed, but amyloid PET remains the scan that actually determines eligibility for approved Alzheimer's drugs. The sections below explain what each scan does, what changed with this approval, and what a patient or caregiver can realistically expect going into an appointment.
Medical information disclaimer: This article is for general educational purposes only and does not provide medical advice, diagnosis, or treatment. Always consult a physician or other qualified health professional about symptoms, medications, tests, or treatment decisions.
Official resources:
- Read the official guidance from Healio — Use this primary source to verify the official guidance.
- Read the official notice from Practicalneurology — Use this primary source to verify the official announcement.
Table of Contents
- What Tauklarify Is and Why It Just Became a Bigger Deal
- How Tauklarify Compares to Amyloid PET
- Why Tauklarify Found More Tau Than the Older Tracer
- What This Means for Someone With MCI Right Now
- Frequently Asked Questions
What Tauklarify Is and Why It Just Became a Bigger Deal
Tauklarify, known chemically as florquinitau F 18 and previously tracked in trials as MK-6240, is a radioactive imaging agent injected before a PET scan to highlight tau neurofibrillary tangles — twisted protein fibers inside brain cells that build up as Alzheimer's progresses. The FDA approved it for adults with cognitive impairment who are being evaluated for Alzheimer's disease, making it only the second F-18 tau tracer ever cleared in the United States, according to AuntMinnie's coverage of the approval. Before this approval, the only tau PET tracer available was Tauvid (flortaucipir), which Avid/Lilly brought to market in 2020 and which held the field to itself for six years, per the same AuntMinnie report.
That lack of competition mattered because tau tracers are not interchangeable — as the next section explains, Tauklarify appears to catch tau pathology that Tauvid misses. Tauklarify is given as a single intravenous dose of about 185 MBq (5 mCi), and the resulting scan is read qualitatively as either positive or negative for tau pathology. Safety data came from 1,734 subjects, with headache, nausea, injection-site reactions, dizziness, and abdominal discomfort as the most commonly reported reactions, according to Lantheus's approval history on Drugs.com.
How Tauklarify Compares to Amyloid PET
Amyloid PET and tau PET look for two different proteins involved in Alzheimer's disease, and they answer different clinical questions. Amyloid PET detects amyloid plaques, the buildup that current Alzheimer's drugs like lecanemab and donanemab are designed to clear, and it is the scan used to confirm whether a patient qualifies for those treatments. Tau PET, including Tauklarify, instead maps where tau tangles have accumulated, which tracks more closely with symptom severity and disease stage. Under the Society of Nuclear Medicine and Molecular Imaging's updated Appropriate Use Criteria, amyloid PET is rated appropriate in MCI mainly to confirm drug eligibility, while tau PET is rated complementary — useful for staging how advanced the disease is, not for deciding who can start treatment.
The panel does not recommend ordering both scans routinely together, according to SNMMI and the Alzheimer's Association's January 2025 guidance. In practice, that means a positive amyloid scan can open the door to a drug prescription, while a tau scan generally cannot. FDA approval for Tauklarify rested on two blinded-reader studies spanning more than 500 subjects across three trials. Readers agreed with the pathology or clinical reference standard 68% to 88% of the time on positive scans and 93% to 99% of the time on negative scans, according to Practical Neurology's summary of the approval data. Those ranges mean a negative Tauklarify scan is fairly reliable at ruling pathology in or out, but a positive reading still carries meaningful uncertainty depending on the study.
Why Tauklarify Found More Tau Than the Older Tracer
A May 2026 trial called HEAD compared Tauklarify directly against Tauvid in 775 enrolled participants, with 682 completing both scans within 45 days of each other. The tracers did not agree: Tauklarify flagged tau pathology in 15% of amyloid-positive but cognitively unimpaired people, compared with 6% for Tauvid, and in 28% of cognitively impaired people, compared with 16% for Tauvid, according to AuntMinnie's report on the HEAD trial results. That gap is roughly double in both groups, and it is the core reason Tauklarify's approval matters clinically rather than just as a second option on a label.
The same HEAD study also found Tauklarify more accurate than Tauvid at distinguishing Alzheimer's-related cognitive impairment from other causes, which is the practical edge clinicians are likely to weigh when choosing between the two tracers, according to a second AuntMinnie report on the trial's discriminative accuracy findings. Higher sensitivity is not an unqualified upgrade, though. The FDA label is explicit that a negative Tauklarify scan does not rule out tau pathology, and a positive scan does not confirm Alzheimer's disease on its own — imaging findings still need to be read alongside the clinical picture, per the FDA label summary reported by Pharmacally. The label also excludes non-Alzheimer's tauopathies such as progressive supranuclear palsy and corticobasal degeneration, so Tauklarify is not approved for sorting out those conditions.
What This Means for Someone With MCI Right Now
For a person recently diagnosed with mild cognitive impairment, Tauklarify does not change the path to an Alzheimer's drug. Eligibility for lecanemab or donanemab still runs through an amyloid PET scan or an equivalent biomarker test, not a tau scan, per the SNMMI/Alzheimer's Association criteria cited above. A tau PET scan, whether Tauklarify or Tauvid, is more likely to come into play after an amyloid-positive result, when a clinician wants a clearer sense of how far tau pathology has spread.
Coverage is also uneven between the two scan types. Medicare's old national policy that limited amyloid PET to one lifetime scan has been removed, leaving coverage decisions to local Medicare Administrative Contractors, according to the American College of Radiology. No equivalent national coverage policy exists yet for tau PET, so whether insurance pays for a Tauklarify scan in an MCI patient depends on the individual payer, according to the Alzheimer's Association's care pathway guidance. A reasonable way to think through the two scans at an appointment: The bottom line for 2026: Tauklarify gives clinicians a more sensitive window into tau pathology than they've had before, but it slots in as an added staging tool after amyloid testing, not a replacement for the scan that unlocks treatment.
- Ask whether an amyloid PET scan has already confirmed or ruled out amyloid plaques — this is the scan tied to drug eligibility.
- If amyloid is positive, ask whether a tau PET scan (Tauklarify or Tauvid) would add useful staging information for your specific case.
- Ask your insurer directly about tau PET coverage before scheduling, since no blanket Medicare policy covers it yet.
- Confirm your evaluation is for Alzheimer's-type impairment, since Tauklarify's label excludes other tauopathies like progressive supranuclear palsy.
Frequently Asked Questions
Does a positive Tauklarify scan mean I have Alzheimer's disease?
No. The FDA label states a positive scan does not confirm histopathologically verified Alzheimer's disease on its own, per Pharmacally's summary of the label; it must be interpreted alongside clinical findings.
Can Tauklarify replace my amyloid PET scan?
No. Amyloid PET remains the scan used to confirm eligibility for drugs like lecanemab and donanemab, while tau PET is rated complementary for staging, according to SNMMI/Alzheimer's Association guidance.
Will Medicare pay for a Tauklarify scan?
There is no national Medicare coverage policy for tau PET yet, so it depends on your local Medicare contractor or private insurer, per the Alzheimer's Association.
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