Skip to main content

Outage notice:

Due to the global information outage that occurred Friday, Quest is taking swift action to respond, recover and restore our operations. Our Patient Services are operating with reduced capacity so you may experience longer wait and service times. Our Customer Contact teams are currently unavailable. We appreciate your patience as we work toward returning to normal operations. 


Cognitive health assessments and lab tests designed to enhance the Alzheimer’s disease and dementia care pathway

Alzheimer’s disease is the most common cause of dementia, affecting over 6M people in the US.1 Diagnosis and care for patients with cognitive impairment is rapidly evolving, making assessing Alzheimer’s disease pathophysiology, as well as other dementias, key to timely intervention.

Improvement of patient outcomes and care pathways drives our commitment to offer one of the industry’s most comprehensive portfolios of lab tests for Alzheimer’s disease and dementia to help assess potential risk.

Quest AD-Detect® is a portfolio of blood-based risk assessment offerings that can help provide better understanding of a patient’s potential risk for dementia or Alzheimer’s disease. For patients who may want a less invasive option, a simple blood test can be the first step in taking action and help to determine if more comprehensive testing is needed.

Quest AD-Detect® Beta-Amyloid 42/40 Ratio

This test assesses beta-amyloid 42/40 (Aβ42/40) ratio via plasma. This ratio measures levels of 2 beta-amyloid peptides, where certain ratio results may suggest a risk of developing Alzheimer’s disease.2 Blood-based amyloid testing provides an accessible, affordable tool as part of Alzheimer’s disease risk assessment and ongoing monitoring, aiding in evaluation of further comprehensive testing needs.

Quest AD-Detect® Apolipoprotein (ApoE) Isoform

It’s critical to understand ApoE status for patients considering amyloid-modifying therapies. This test can provide insights on the presence of ApoE isoforms, a well-known biomarker associated with risk of developing Alzheimer’s disease.2 Insights into a patient’s ApoE status can help assess the risk of amyloid-related imaging abnormalities (ARIA) in patients considering amyloid-modifying therapeutics. Quest (data on file) and others3,4 have shown that the results of phenotyping are 100% concordant with ApoE genotyping results.

Quest AD-Detect® p-tau181

This test is used to detect phosphorylated tau (p-tau181) proteins, one of the hallmark biomarkers involved in the diagnosis and staging of Alzheimer’s disease. P-tau181 concentrations increase over time within plasma as Alzheimer’s disease progresses.5,6 Routine monitoring of p-tau181 levels via plasma is ideal to support care pathways as it is less invasive, less expensive, and more practical than other methods. Combined plasma p-tau and Aβ42/40 biomarker testing has been shown to help identify patients at risk of experiencing faster cognitive decline7 and which patients can benefit from further diagnostic testing.

Quest AD-Detect® p-tau217

Plasma testing for the phosphorylated tau217 (p-tau217) biomarker can help assess whether mild cognitive impairment (MCI) or dementia is caused by Alzheimer’s disease.8-10

Current research indicates that plasma p-tau—including p-tau217—is concordant with amyloid status defined by either cerebrospinal fluid (CSF) biomarker testing or positron emission tomography (PET) scan analysis and has been shown to predict progression to Alzheimer’s disease.8-12 It can differentiate between Alzheimer’s disease and non-Alzhiemer's disease neurodegenerative conditions and identify patients who may benefit from further diagnostic testing.8-10

This test leverages our lab services and artificial intelligence (AI) technology from uMETHOD Health to deliver personalized treatment recommendations that address key contributors to memory loss, dementia, and mild cognitive impairment. RestoreU dementia risk assessment can help generate personalized care plans with evidence-based, actionable treatment recommendations. Read our press release about the RestoreU service.

This test measures beta-amyloid 40 (Aβ40) as well as Aβ42 in CSF, rather than Aβ42 alone. Using the ratio of Aβ42/40 improves sensitivity and specificity for Alzheimer’s patients.

This test combines ApoE results with Aβ42/40 ratio into an algorithm to assess Alzheimer’s disease risk, and can help assess the risk of amyloid related imaging abnormalities (ARIA) in patients considering amyloid-modifying therapeutics.

This test combines 3 biomarkers, phospho-tau, total tau, and Aβ42, to help you provide clinically relevant information regarding Alzheimer’s disease staging that may help guide patient management.

This test can provide insights into a patient’s ApoE status. ApoE is a key biomarker associated with an increased risk of developing Alzheimer’s disease.13

Sign up to receive updates on Alzheimer’s disease and dementia blood tests.

Sign up


1. CDC. Accelerating risk reduction and promoting brain health. Updated July 29, 2019. Accessed May 18, 2023.
2. Nakamura A, Kaneko N, Villemagne V, et al. High performance plasma amyloid-B biomarkers for Alzheimer’s disease. Nature. 2018;554(7691):249-254. doi:10.1038/nature25456
3. Nishimura M, Satoh M, Nishimura S, et al. Human apolipoprotein E resequencing by proteomic analysis and its application to serotyping. PLoS ONE. 2014;9(1):e85356. doi:10.1371/journal.pone.0085356
4. Kirmess KM, Meyer MR, Holubasch MS, et al. The PrecivityAD test: accurate and reliable LC-MS/MS assays for quantifying plasma amyloid beta 40 and 42 and apolipoprotein E proteotype for the assessment of brain amyloidosis. Clin Chim Acta. 2021;519:267-275. doi:10.1016/j.cca.2021.05.011
5. Lantero Rodriguez J, Karikari TK, Suárez-Calvet M, et al. Plasma p-tau181 accurately predicts Alzheimer’s disease pathology at least 8 years prior to postmortem and improves the clinical characterisation of cognitive decline. Acta Neuropathol. 2020;140(3):267-278. doi:10.1007/s00401-020-02195-x
6. Brickman AM, Manly JJ, Honig LS, et al. Plasma p-tau181, p-tau217, and other blood-based Alzheimer’s disease biomarkers in a multi-ethnic, community study. Alzheimers Dement. 2021;17(8):1353-1364. doi:10.1002/alz.12301
7. Meyer PF, Ashton NJ, Karikari TK, et al. Plasma p-tau231, p-tau181, PET biomarkers, and cognitive change in older adults. Ann Neurol. 2022;91(4):548-560. doi:10.1002/ana.26308
8. Thijssen EH, Joie RL, Strom A, et al. Plasma phosphorylated tau 217 and phosphorylated tau 181 as biomarkers in Alzheimer’s disease and frontotemporal lobar degeneration: a retrospective diagnostic performance study. Lancet Neurol. 2021;20(9):739-752. doi:10.1016/s1474-4422(21)00214-3
9. Palmqvist S, Janelidze S, Quiroz YT, et al. Discriminative accuracy of plasma phospho-tau217 for Alzheimer disease vs other neurodegenerative disorders. JAMA. 2020;324(8):772-781. doi:10.1001/jama.2020.12134
10. Ashton NJ, Brum WS, Molfetta GD, et al. Diagnostic accuracy of a plasma phosphorylated tau 217 immunoassay for Alzheimer disease pathology. JAMA Neurol. 2024;81(3):255-263. doi:10.1001/jamaneurol.2023.5319
11. Mielke MM, Dage JL, Frank RD, et al. Performance of plasma phosphorylated tau 181 and 217 in the community. Nat Med. 2022;28(7):1398-1405. doi:10.1038/s41591-022-01822-2
12. Therriault J, Ashton NJ, Pola I, et al. Comparison of two plasma p-tau217 assays to detect and monitor Alzheimer’s pathology. eBioMedicine. 2024;102:105046. doi:10.1016/j.ebiom.2024.105046
13. Kim J, Basak JM, Holtzman DM. The role of apolipoprotein E in Alzheimer’s disease. Neuron. 2009;63(3):287-303. doi:10.1016/j.neuron.2009.06.026