p-tau181

check icon Optimal Result: 0 - 0.95 pg/mL.

p-tau181 (Phosphorylated-Tau 181)

What p-tau181 shows

p-tau181 is a form of the tau protein that has been modified (phosphorylated) at threonine 181. Higher-than-normal levels of p-tau181 reflect Alzheimer’s-type brain changes—specifically the buildup of amyloid plaques and tau tangles.

This marker can be measured in cerebrospinal fluid (CSF) or blood (plasma or serum). In CSF, p-tau181 has long been a core biomarker for Alzheimer’s disease (AD). Blood-based p-tau181 tests are a newer, less-invasive option that still give important insights and can help separate AD from other forms of dementia.

Why this test matters for Alzheimer’s disease

  • Early insight with a blood test: A simple blood draw may provide early information about brain changes linked to Alzheimer’s, potentially reducing the need for spinal taps or specialized brain scans.

  • Clearer diagnosis: Elevated p-tau181 supports the presence of Alzheimer’s-type changes and helps distinguish AD from other memory disorders when combined with clinical evaluation.

  • Care planning and monitoring: Results can guide decisions about further tests and help establish a baseline for tracking changes over time or before starting treatment.

How the p-tau181 test is done

Laboratories measure p-tau181 using immunoassays or mass spectrometry. Each method has its own reference range and cutoffs, so results from different labs are not directly comparable. Always rely on the numbers and reference intervals printed on your own test report.

Who might benefit from this test

  • People being evaluated for new or worsening memory, language, or thinking problems

  • Patients where the difference between Alzheimer’s disease and another type of dementia isn’t clear

  • Individuals being considered for PET scans or CSF testing, as a way to triage next steps

  • Patients starting treatment, where a baseline value is useful for future comparison

How to understand your result

Always interpret results using the reference range shown on your report and with your clinician’s guidance.

  • Higher p-tau181: Increases the likelihood of Alzheimer’s-type pathology. Your clinician may suggest confirmatory tests (amyloid PET, CSF biomarkers) if results could affect treatment or care decisions.

  • Lower p-tau181: Makes Alzheimer’s-type changes less likely at the time of testing. Other causes for symptoms may be explored.

  • Borderline/gray zone: Like being “on the fence.” Your clinician may recommend repeating the test, adding other markers (such as Aβ42/40 ratio or p-tau217), or proceeding with imaging depending on your overall risk.

Practical tips for reading results

  • Combine p-tau181 with the Aβ42/40 ratio or other companion markers for greater accuracy.

  • Results should always be interpreted alongside your medical history, neurologic exam, cognitive testing, and imaging findings when available.

  • Trends over time are often more informative than a single result, especially if symptoms evolve.

Factors that can change your p-tau181 result

  • Test method and lab platform: Different labs use different techniques, so ranges vary.

  • Sample handling: Tube type, processing time, and storage can affect results, but labs standardize these steps.

  • Medical conditions: Serious illness, kidney or liver disease, or mixed neurodegenerative disorders can complicate interpretation.

  • Population studied: Performance is best in adults with symptoms being evaluated at memory clinics. Routine screening for people without symptoms is not currently recommended.

Related biomarkers often ordered together

  • Aβ42/40 ratio (blood or CSF): Strengthens accuracy when paired with p-tau181.

  • p-tau217 / p-tau231: Other phosphorylated forms of tau; p-tau217 may outperform p-tau181 in some studies.

  • Total tau and NfL (neurofilament light): Provide information on general brain cell injury or neurodegeneration.

  • Imaging and cognitive testing: MRI, FDG-PET, amyloid or tau PET scans, and structured cognitive assessments give additional context.

Important limitations to know

  • Not a stand-alone diagnosis: p-tau181 indicates the likelihood of Alzheimer’s-type pathology but must be interpreted with clinical findings and, often, confirmatory tests.

  • Borderline results are common: These may require repeat testing or additional biomarkers.

  • Assay differences matter: Numbers can’t be compared across labs or platforms.

FAQs

Is there a universal normal range for p-tau181?
No. Cutoffs depend on the laboratory method. Always use the range listed on your report.

How does p-tau181 compare with p-tau217?
Both reflect Alzheimer’s biology. Many studies suggest p-tau217 is slightly more accurate, but p-tau181 is widely available, well-researched, and still highly useful.

If my p-tau181 is high, does that mean I definitely have Alzheimer’s?
No. A high result increases the likelihood but is not a stand-alone diagnosis. Your clinician may recommend confirmatory tests.

Do I still need imaging or a spinal tap (CSF test)?
Sometimes. p-tau181 can reduce the need for invasive tests, but confirmatory studies may be needed if results are borderline, conflicting, or would change treatment decisions.

What to do next

  • Check which assay/platform your lab used and note the specific cutoff reported.

  • Discuss results in the context of your symptoms, family history, cognitive testing, and imaging results with your clinician.

  • Ask about adding companion biomarkers (Aβ42/40 ratio or p-tau217 if available).

  • Plan follow-up: consider repeat testing or confirmatory PET/CSF studies if results are borderline or if management would change.

  • Use results as a baseline for tracking over time, especially if treatment is started or symptoms progress.

All Your Lab Results.
One Simple Dashboard.

Laboratories

Bring All Your Lab Results Together — In One Place

We accept reports from any lab, so you can easily collect and organize all your health information in one secure spot.

lab corp logo
genova diagnostics logo
quest diagnostics logo
dutch test logo
doctors data logo
vibrant america logo
diagnostic solutions logo
zrt laboratory logo
the great plains laboratory logo
cyrex laboratories logo
spectracell logo

Pricing Table

decoration

Personal plans

$15/ month

Complete Plan

Access your lab reports, explanations, and tracking tools.

  • Import lab results from any provider
  • Track all results with visual tools
  • Customize your reference ranges
  • Export your full lab history anytime
  • Share results securely with anyone
  • Begin with first report entered
  • Cancel or upgrade anytime

$250/ once

Unlimited Account

Pay once, access everything—no monthly fees, no limits.

  • Import lab results from any provider
  • Track all results with visual tools
  • Customize your reference ranges
  • Export your full lab history anytime
  • Share results securely with anyone
  • Receive 10 reports entered for you
  • Skip the $15/month subscription — no recurring payments ever

$45/ month

Pro Monthly

Designed for professionals managing their clients' lab reports

  • Import lab results from any provider
  • Track lab results for multiple clients
  • Customize reference ranges per client
  • Export lab histories and reports
  • Begin with first report entered by us
  • Cancel or upgrade anytime

About membership

What's included in a Healthmatters membership

microscope icon Import Lab Results from Any Source

person icon See Your Health Timeline

book icon Understand What Your Results Mean

textbook icon

textbook icon Visualize Your Results

folder icon

folder icon

card icon Securely Share With Anyone You Trust

Let Your Lab Results Tell the Full Story

What Healthmatters Members Are Saying

5 stars rating

I have been using Healthmatters.io since 2021. I travel all over the world and use different doctors and health facilities. This site has allowed me to consolidate all my various test results over 14 years in one place. And every doctor that I show this to has been impressed. Because with  any health professional I talk to, I can pull up historical results in seconds. It is invaluable. Even going back to the same doctor, they usually do not have the historical results from their facility in a graph format. That has been very helpful.

Anthony

Unlimited Plan Member since 2021

5 stars rating

What fantastic service and great, easy-to-follow layouts! I love your website; it makes it so helpful to see patterns in my health data. It's truly a pleasure to use. I only wish the NHS was as organized and quick as Healthmatters.io. You've set a new standard for health tracking!

Karin

Advanced Plan Member since 2020

5 stars rating

As a PRO member and medical practitioner, Healthmatters.io has been an invaluable tool for tracking my clients' data. The layout is intuitive, making it easy to monitor trends and spot patterns over time. The ability to customize reports and charts helps me present information clearly to my clients, improving communication and outcomes. It's streamlined my workflow, saving me time and providing insights at a glance. Highly recommended for any practitioner looking for a comprehensive and user-friendly solution to track patient labs!

Paul

Healthmatters Pro Member since 2024

Use promo code to save 10% off any plan.

Frequently asked questions

Healthmatters is a personal health dashboard that helps you organize and understand your lab results. It collects and displays your medical test data from any lab in one secure, easy-to-use platform.

  • Individuals who want to track and understand their health over time.
  • Health professionals, such as doctors, nutritionists, and wellness coaches, need to manage and interpret lab data for their clients.

With a Healthmatters account, you can:

  • Upload lab reports from any lab
  • View your data in interactive graphs, tables, and timelines
  • Track trends and monitor changes over time
  • Customize your reference ranges
  • Export and share your full lab history
  • Access your results anytime, from any device

Professionals can also analyze client data more efficiently and save time managing lab reports.

Healthmatters.io personal account provides in-depth research on 4000+ biomarkers, including information and suggestions for test panels such as, but not limited to:

  • The GI Effects® Comprehensive Stool Profile,
  • GI-MAP,
  • The NutrEval FMV®,
  • The ION Profile,
  • Amino Acids Profile,
  • Dried Urine Test for Comprehensive Hormones (DUTCH),
  • Organic Acids Test,
  • Organix Comprehensive Profile,
  • Toxic Metals,
  • Complete Blood Count (CBC),
  • Metabolic panel,
  • Thyroid panel,
  • Lipid Panel,
  • Urinalysis,
  • And many, many more.

You can combine all test reports inside your Healthmatters account and keep them in one place. It gives you an excellent overview of all your health data. Once you retest, you can add new results and compare them.

If you are still determining whether Healthmatters support your lab results, the rule is that if you can test it, you can upload it to Healthmatters.

shield icon

We implement proven measures to keep your data safe.

At HealthMatters, we're committed to maintaining the security and confidentiality of your personal information. We've put industry-leading security standards in place to help protect against the loss, misuse, or alteration of the information under our control. We use procedural, physical, and electronic security methods designed to prevent unauthorized people from getting access to this information. Our internal code of conduct adds additional privacy protection. All data is backed up multiple times a day and encrypted using SSL certificates. See our Privacy Policy for more details.

gdpr compliance image hipaa compliance image