Information for Patients and Families
P-tau217 is a blood-based biomarker that can help doctors evaluate whether Alzheimer’s disease biology may be contributing to memory or thinking problems.
Alzheimer’s disease is associated with changes in certain proteins in the brain, including amyloid and tau. P-tau217 is a form of tau that can be measured in blood and is often elevated when Alzheimer’s-related brain changes are present.
A p-tau217 blood test does not diagnose Alzheimer’s disease by itself. The result must be interpreted together with a full clinical evaluation, which may include medical history, cognitive testing, medication review, neurologic examination, brain imaging when appropriate, and other bloodwork to look for reversible causes of memory problems.
This can be ordered by your primary care physician, specialist, or as part of a clinical trial.
Examples of Available P-tau217 Blood Test Options
The following are examples of commercially available blood-based Alzheimer’s biomarker tests that include p-tau217 or a p-tau217-related ratio. Availability, ordering process, intended-use population, and regulatory status may change over time.
ARUP Laboratories
Phospho-Tau 217, Plasma
Ordering / test information:
https://ltd.aruplab.com/Tests/Pub/3019017
C2N Diagnostics
PrecivityAD2
Ordering / test information:
https://c2n.com/precivity-tests/precivityad2-healthcare-providers/
Labcorp
Phosphorylated Tau 217, Plasma
Ordering / test information:
https://www.labcorp.com/tests/484390/phosphorylated-tau-217-ptau-217-plasma
Labcorp
Lumipulse pTau-217/Beta Amyloid 42 Ratio
Ordering / test information:
https://www.labcorp.com/treatment-areas/neurology/clinical-testing/ptau217betaamyloid42ratio
Mayo Clinic Laboratories
PrecivityAD2, Plasma
Ordering / test information:
https://www.mayocliniclabs.com/test-catalog/Overview/621652
Quest Diagnostics
Quest AD-Detect Phosphorylated tau217, Plasma
Ordering / test information:
Quest Diagnostics
AD-Detect ABeta 42/40 and p-tau217 Evaluation, Plasma
Ordering / test information:
What Can the Results Mean?
A positive result may increase the likelihood that Alzheimer’s disease biology is present.
A negative result may make Alzheimer’s disease biology less likely, although it does not rule out every cause of cognitive symptoms.
An intermediate or indeterminate result may mean that additional evaluation is needed.
Regardless of the result, the blood test is only one part of the diagnostic process. Memory symptoms can have many causes, including sleep problems, depression, medication effects, thyroid disease, vitamin deficiencies, vascular disease, Parkinsonian disorders, frontotemporal dementia, Lewy body disease, and others.
Why This Testing Matters
Early detection matters. Alzheimer’s disease biology can begin many years before symptoms become obvious — in some cases up to 10–20 years before noticeable memory or thinking changes. That means there may be a long window during which the disease process is developing but not yet easily recognized through routine clinical evaluation alone.
Blood-based biomarkers such as p-tau217 may help identify Alzheimer’s-related changes earlier and may make evaluation more accessible than older approaches that often relied on amyloid PET scans or spinal fluid testing.
This is especially important because clinical trials are now studying Alzheimer’s disease at earlier stages, including prevention-focused trials for people who may have Alzheimer’s-related brain changes before significant symptoms develop. Identifying these changes may help patients and families learn whether they could be considered for additional evaluation, research opportunities, or clinical trial screening.
For patients with memory or thinking symptoms, p-tau217 testing may also help determine whether they could qualify for Alzheimer’s disease clinical trials. Many research studies require evidence of Alzheimer’s-related biology, such as amyloid or tau pathology, before a patient can enroll. Blood-based testing may help guide that process and identify patients who should be considered for additional study screening.
Important Limitations
P-tau217 blood testing is not a substitute for clinical judgment.
A positive result does not automatically mean that Alzheimer’s disease is the only cause of a patient’s symptoms.
A negative result does not eliminate the need to evaluate other neurologic, psychiatric, medication-related, sleep-related, metabolic, or vascular causes of cognitive impairment.
Some tests may produce intermediate or indeterminate results.
Insurance coverage and patient cost may vary.
Test availability and regulatory status may change.
Blood biomarker results may help guide referral, further diagnostic testing, and treatment discussions, but they should be interpreted in the context of the whole patient.
