Quest Diagnostics has introduced a new blood test aimed at assisting physicians in confirming amyloid brain pathology related to Alzheimer's disease in individuals with mild cognitive impairment (MCI) or dementia.
The test, known as AD-Detect Abeta 42/40 and p-tau217 Evaluation, is said to combine amyloid beta (AB) 42/40 blood level outcomes, which are determined by Quest’s tandem mass spectrometry techniques with p-tau217 blood levels as measured by an in vitro immunoassay.
These outcomes are utilised for generating the AD-Detect Likelihood Score, which is said to be a composite interpretation derived from an algorithm validated leveraging “well-characterised cohort” from the 1Florida Alzheimer's Disease Research Center.
This test panel expands upon Quest's previous AD-Detect tests that measure AB 42/40 and p-tau217, along with p-tau181 and the ApoE isoform, which are used to assess AD risk.
Quest noted that in Alzheimer's, amyloid proteins form plaques in the brain, leading to tau proteins twisting into tangles, which disrupt the cell function of the brain and result in abnormal protein levels in the bloodstream.
According to the company’s researchers, the new test showed a positive predictive value of 89% and a negative predictive value of 89% for detecting the disease in subjects with mild cognitive impairment, with even better predictive values when including the ApoE genetic risk marker.
The test is currently available to physicians across the US, excluding New York.
Individuals can have their blood drawn at any of Quest's nearly 8,000 access points, including patient service centres and mobile phlebotomy services.
Samples will be processed at the company’s lab in California, US.
Quest Diagnostics neurology general manager and vice-president Kathleen Valentine said: "Quest's AD-Detect suite of advanced diagnostics has grown to include a range of validated blood-based biomarkers, giving providers options for personalising testing for the individual patient.
"Quest's innovations in blood testing combined with our broad patient access are making it easier, faster and more affordable to evaluate patients for Alzheimer's and other complex diseases."
In February 2025, Grail partnered with Quest to enable access to its Galleri multi-cancer early detection test for US healthcare providers.
