---
title: A Blood Test Can Now Flag Alzheimer's Pathology Without a Brain Scan
description: A blood test for Alzheimer's pathology is FDA-cleared and coming to Labcorp nationwide. What it detects, what a positive means, and the cost.
author: Dr Marina Nani (Editor-in-Chief)
updated: 2026-08-24T15:15:26.577Z
canonical: https://richhealthmagazine.com/article/alzheimers-blood-test-ptau217-fda-cleared-200564
categories: Longevity & Science
content_type: News
region: United States
publication: Rich Health Magazine
schema_type: Article
---

If you have been worried about your own memory, or watching a parent grope for words that used to come easily, the road to an answer just got shorter. The U.S. Food and Drug Administration has cleared a blood test for Alzheimer's pathology, and Labcorp says it will make the test available across the country in the coming months. For a person 55 or older who is already having trouble with memory or thinking, a routine blood draw at a doctor's office can now do work that until recently required a PET brain scan or a spinal tap.

The test measures phosphorylated tau 217, or pTau-217, a protein in the blood that rises along with amyloid buildup in the brain. Amyloid is one of the hallmarks of Alzheimer's disease. Developed by Roche Diagnostics in collaboration with Eli Lilly, the test is meant for adults who already show signs, symptoms or complaints of cognitive decline, and it returns one of three results: positive, intermediate or negative.

## Labcorp Will Run the Test at Its Own Patient Service Centers

Blood for the pTau-217 test can be drawn in a physician's office or at one of Labcorp's more than 2,200 patient service centers, the company says, with nationwide availability arriving over the coming months. Labcorp describes it as the first and only FDA-cleared single-biomarker blood test that can both rule in and rule out amyloid pathology across primary care and specialty settings, and says its performance is comparable to spinal-fluid testing and PET imaging.

That "first and only" claim rests on a narrow, real distinction. The first blood test for amyloid pathology, a two-biomarker ratio developed by Fujirebio, [was cleared in 2025](https://www.fujirebio.com/en-us/news-events/fujirebio-receives-marketing-clearance-for-lumipulser-g-ptau-217bamyloid-142-plasma-0). The Roche test is the first cleared version built on a single biomarker. pTau-217 itself is not new either; it has been used in research and offered as a lab-developed test for a while. What changed is that a single-biomarker version now carries FDA clearance, and a national lab is putting it within reach of ordinary clinics. It joins Labcorp's existing FDA-cleared pTau-181 test and its Lumipulse pTau-217 and beta-amyloid 42 ratio.

## The Bigger Shift Is Who Can Now Start the New Alzheimer's Drugs

A new class of anti-amyloid drugs, lecanemab (Leqembi) and donanemab (Kisunla), can slow the disease for some patients, but a doctor can only prescribe them once amyloid is confirmed. Confirmation historically meant a costly scan or a spinal tap, and [lecanemab's labeling requires that confirmation](https://www.alz.org/alzheimers-dementia/treatments/lecanemab-leqembi) before treatment begins. A blood test lowers that gate. For a family weighing whether one of these therapies is even an option, a blood draw is a far easier first step than booking a PET scan.

## A Positive Result Is Not a Diagnosis

A positive result means amyloid is present. It does not mean a person has dementia, and it does not mean they are certain to develop it. Amyloid is common in older brains even without symptoms; by around age 80, roughly a third of cognitively healthy people carry amyloid pathology. That is why the test is only for people who already have cognitive symptoms, and why a doctor reads it alongside other findings rather than treating it as a verdict on its own.

The test is very good at not missing amyloid, so a positive result leads to more steps rather than a conclusion. For someone who tests positive or intermediate, the usual next steps are further evaluation, possibly imaging, and a conversation with a clinician about whether an anti-amyloid drug makes sense.

## FAQ

**Q: How much does an Alzheimer's blood test cost, and does insurance or Medicare cover it?**
Out-of-pocket retail prices for these Alzheimer's blood tests have run roughly $240 to $399. Insurance and Medicare coverage is still uncertain and evolving, so check with your plan and the lab before assuming the test will be paid for.

**Q: Who is the test for, and can I ask my doctor for it?**
It is intended for adults 55 and older who are already experiencing memory or thinking problems, not for screening people who feel well, and it has not been shown to predict whether a symptom-free person will later develop Alzheimer's. If you have cognitive symptoms, your doctor can decide whether the test fits your situation and order it.

**Q: What is pTau-217?**
It is a form of the tau protein, phosphorylated tau 217, that can be measured in blood and rises in step with amyloid buildup in the brain. Measuring it gives clinicians a window into Alzheimer's-related changes without a scan or spinal tap.