AD-Detect® ABeta 42/40, p-tau217, and ApoE Evaluation, Plasma

Test Code

16493

CPT Codes
82233, 82234, 84393, 82542

Includes

AD-Detect Likelihood Score with ApoE Interpretation
AD-Detect Beta-Amyloid 42/40 Ratio, Plasma
AD-Detect Phosphorylated tau217, Plasma
AD-Detect ApoE Isoform, Plasma
AD-Detect Likelihood Score with ApoE

Preferred Specimen

4 mL total frozen plasma collected in K2 EDTA (lavender-top) tubes, split into 3 equal aliquots

Patient Preparation
Patients should be cautioned to stop biotin consumption at least 72 hours prior to collection of a sample

Minimum Volume

3.6 mL

Instructions

Quest Diagnostics does not recommend performing this test on individuals under the age of 18. Pre-test and post-test counseling is strongly recommended.

Collect blood into two K2 EDTA plasma tubes and mix by inversion 10 times. Centrifuge to separate plasma from cells within 1 hour of collection. Carefully transfer plasma into three separate polypropylene tubes or three separate Quest issued polypropylene pour-off/transfer tubes. Do not transfer to conical tubes. Store and ship frozen.

Transport Container

See Collection Instructions

Transport Temperature

Frozen

Specimen Stability

Room temperature: Unacceptable
Refrigerated: Unacceptable
Frozen: 28 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Moderate or gross hemolysis • Specimen collected in a glass, polystyrene, or polycarbonate tube • Specimen collected in K3 EDTA tube or K2 EDTA gel separator tube

Methodology
Immunoassay (IA) • Liquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS)

Setup Schedule

Set up: Mon-Sat; Report available: 4-7 days

Reference Range

ABeta 42	Not Established
ABeta 40	Not Established
ABeta 42/40 Ratio	≥0.170
AD Detect ptau217, Plasma	≤0.15 pg/mL
AD Detect® ApoE Isoform, Plasma	Not Established

AD Detect® Likelihood Score w/ApoE
Likelihood of amyloid PET positivity
Low Likelihood	<0.3714
Indeterminate	0.3714 to 0.5375
High Likelihood	>0.5375

Clinical Significance

This test combines ABeta 42/40 ratio, p-tau217 levels, and APOE4 allele count to report out the likelihood that a patient suspected of Alzheimer's disease (AD) has a high, indeterminate, or low likelihood of amyloid pathology consistent with AD as valuated with amyloid PET.

Independent measurement and interpretation of plasma amyloid ratios (ABeta 42/40), phosphorylated tau 217 (p-tau217), and APOE status provide clinically valuable insight into patient risk for development of Alzheimer's disease. Combining these core markers for AD pathology into a single analytical interpretation has been shown to significantly improve predictive performance and accuracy in assessing amyloid PET positivity and confirming pathology consistent with a diagnosis of Alzheimer's disease. [1]

AD-Detect® ABeta 42/40, p-tau217, and ApoE Evaluation, Plasma is intended for patients with cognitive impairment in the age range of 50-85. This panel meets established performance criteria for confirming a diagnosis of Alzheimer's disease utilizing plasma biomarkers. [1,2] The results of this test should be interpreted in the context of pertinent clinical, family history, physical examination, and image findings.
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References
1. Weber D, et al. Neurol Clin Pract. 2025; 15(6):e200546. doi:10.1212/CPJ.0000000000200546
2. Palmqvist S, et al. Alzheimers Dement. 2025; 21(7):e70535. doi: 10.1002/alz.70535

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.