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

Test Code

14258

CPT Codes
82233, 82234, 84393

Includes

AD-Detect™ Likelihood Score Interpretation
Quest AD-Detect™ Beta-Amyloid 42/40 Ratio, Plasma
Quest AD-Detect™ Phosphorylated tau217(p-tau217), Plasma
AD-Detect™ Likelihood Score

Preferred Specimen

2.5 mL total plasma collected in a K2 EDTA (lavender-top) tube split into two equal aliquots

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

Minimum Volume

1.2 mL

Instructions

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

Collect blood into a K2 EDTA (lavender-top) tube and mix by inversion 10 times. Centrifuge to separate plasma from cells within 1 hour of collection. Carefully transfer plasma into 2 separate polypropylene tubes or 2 separate Quest issued polypropylene pour-off/transfer tubes. Do not transfer to conical tubes. Store frozen.

Transport Container

Transport tube (x2)

Transport Temperature

Frozen

Specimen Stability

Room temperature: Unacceptable
Refrigerated: 72 hours
Frozen: 28 days

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

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

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

FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule

Set up: Mon-Sat; Report available: 4-6 days

Reference Range

ABeta 42	Not Established
ABeta 40	Not Established
ABeta 42/40 Ratio	≥0.170
AD Detect p-tau217	≤0.15 pg/mL

AD Detect Likelihood Score
Likelihood of amyloid PET positivity
Low Likelihood	<0.3254
Indeterminant	0.3254-0.6460
High Likelihood	>0.6460

Clinical Significance

Intended use is for Alzheimer's Diagnosis. Independent measurement and interpretation of plasma amyloid ratios (AB42/40) and phosphorylated tau levels (p-tau181 and p-tau217) provide clinically valuable insight into patient risk for development of Alzheimer's disease. However, by combining core AD pathological markers for a single analytical interpretation have been shown to significantly improve predictive performance and accuracy for detecting amyloid positivity and confirming a diagnosis of Alzheimer's disease. The AD-Detect™ ABeta 42/40 and p-tau217 Evaluation, Plasma evaluates a patient's plasma AB42/40 ratios and p-tau217 levels reporting out the likelihood that a symptomatic patient suspected of AD has a High, Indeterminant, or Low likelihood of amyloid pathology consistent with AD. This panel meets established performance criteria for confirming a diagnosis of Alzheimer's disease utilizing plasma biomarkers.

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.