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HelpTest Code LAB3963 Alzheimer's Disease Evaluation, Spinal Fluid
Performing Laboratory
Barnes-Jewish Hospital Laboratory
Methodology
Electrochemiluminescence Immunoassay (ECLIA)
Literature References: Package inserts: Beta-Amyloid (1-42) CSF II, 02/2023; Phospho-Tau (181P) CSF, 12/2022; Total-Tau CSF, 03/2024.
Specimen Requirements
Patient Preparation: For 12 hours before specimen collection do not take multivitamins or dietary supplements containing biotin (vitamin B7), which is commonly found in hair, skin, and nail supplements and multivitamins.
Specimen Type: CSF
Container/Tube: Alzheimer's Disease Evaluation Collection Kit - Sarstedt CSF False Bottom Tube 63.614.625 (2.5 mL) Contact BJH Customer Service for collection kit at 314-362-1470.
Specimen Volume: 2 mLs
Collection Instructions:
1. Perform lumbar puncture and discard the first 1 to 2 mL of cerebrospinal fluid (CSF).
2. Collect CSF directly into one of the listed collection tubes until the tube is at least 50% full.
3. Send CSF specimen in original collection tube. Do not aliquot.
Note: Polystyrene collection tubes are not acceptable. Exposure of CSF to polystyrene tubes may result in falsely low Abeta42 concentrations.
Day(s) Test Set Up
Tuesday, Friday when received by 13:00.
Test Classification and CPT Coding
83520 x 3
Reference Values
Beta-Amyloid (1-42) CSF (Abeta42): ≥ 514 pg/mL
Total-Tau CSF: ≤ 431 pg/mL
Phospho-Tau CSF: ≤ 40.9 pg/mL
pTau/Abeta42 Ratio: ≤ 0.0280
Specimen Transport Temperature
Refrigerated (preferred)
Specimen Stability
| Specimen | Temperature | Stability |
| CSF | Ambient | 12 hours |
| Refrigerated (preferred) | 14 days | |
| Frozen | 60 days |
Laboratory Processing Instructions
Test performed in BJH Core Lab. Deliver to the Cobas 8000 for testing. Completed samples are stored frozen for 30 days.
LOINC
98492-2