Labcorp intends to offer the Elecsys pTau181 assay, the only blood test cleared by the U.S. Food and Drug Administration (FDA) to screen for Alzheimer’s disease and other causes of cognitive decline. Developed by Roche Diagnostics, Labcorp is planning to make the test available throughout the United States by early 2026.

An estimated 7.2 million Americans are living with Alzheimer’s disease, a number expected to nearly double by 2050. Cognitive changes are often first identified during routine care visits, but Alzheimer’s biomarker testing has traditionally required a specialist referral and advanced invasive testing. The Elecsys pTau181 test is intended for adults ages 55 and older with signs, symptoms or complaints of cognitive decline. Clinicians can order the test to help rule out Alzheimer’s-related amyloid pathology and identify patients who may benefit from further evaluation.

“Many patients presenting with cognitive symptoms don’t have Alzheimer’s disease, so helping clinicians rule it out can be just as critical as confirming it,” Labcorp Chief Medical and Scientific Officer Dr. Brian Caveney said. “As a leader in neurology with a portfolio of Alzheimer’s tests, Labcorp is proud to make the FDA-cleared Elecsys pTau181 test widely available—helping physicians identify the causes of cognitive decline and guide timely, appropriate care.”

The Elecsys pTau181 test measures phosphorylated Tau (pTau) 181 protein in human plasma, a key biomarker for Alzheimer’s pathology, including amyloid plaque and tau aggregate pathology. According to Roche, clinical results demonstrated the test could rule out Alzheimer’s pathology with a 97.9% negative predictive value (NPV). A negative test result is consistent with a negative amyloid positron emission tomography (PET) scan result and reduced likelihood that a patient’s cognitive impairment is due to amyloid pathology. These patients, however, should be further evaluated for other causes of cognitive decline. Patients with an initial positive result should be further tested to determine whether the amyloid pathology is causing cognitive impairment. 

Performed through a simple blood draw, the test offers an accessible, more affordable and less invasive alternative to traditional tests such as cerebrospinal fluid (CSF) testing obtained through lumbar puncture and PET scans. Once the test is ordered, the blood draw can be completed in a doctor’s office or at any of Labcorp’s more than 2,200 patient service centers (PSCs) nationwide.

Since March 2023, Labcorp has offered a laboratory-developed test (LDT) version of pTau181, and in October 2023, added it to the company’s ATN Profile—a panel combining three key biomarkers to identify and assess biological changes associated with Alzheimer’s disease. Most recently, Labcorp launched the FDA-cleared Lumipulse pTau-217/Beta Amyloid 42 Ratio to help diagnose Alzheimer’s disease for use in specialty care settings.

Labcorp provides laboratory services that helps doctors, hospitals, pharmaceutical companies, researchers and patients make clear and confident decisions. The company’s nearly 70,000 employees serve clients in approximately 100 countries, provided support for more than 75% of the new drugs and therapeutic products approved by the FDA last year, and perform more than 700 million tests annually for patients worldwide.