Quest AD-Detect® Phosphorylated tau181(p-tau181), Plasma

Test Code

13690

CPT Codes
83520

Preferred Specimen

1 mL plasma collected in an EDTA (lavender-top) tube

Patient Preparation
Dietary supplements containing biotin may interfere in assays and may skew results to be either falsely high or falsely low. For patients receiving the recommended daily doses of biotin, draw samples at least 8 hours following the last biotin supplementation. For patients on mega-doses of biotin supplements, draw samples at least 72 hours following the last biotin supplementation.

Minimum Volume

0.5 mL

Transport Temperature

Room temperature

Specimen Stability

Room temperature: 14 days
Refrigerated: 22 days
Frozen: 22 days

Methodology
Electrochemiluminescence (ECLIA)

Setup Schedule

Set up: Mon-Sat; Report available: 2-4 days

Reference Range

<55 years	≤0.86 pg/mL
≥55 years	≤1.07 pg/mL

Clinical Significance

p-tau181 is a diagnostic biomarker for Alzheimer's Disease (AD) that is useful in identifying patients with underlying AD tau pathology. It can predict the cognitive decline in AD/MCI patients and correlates with amyloid and tau PET results.

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.