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HelpOrder Code ADEVL Alzheimer Disease Evaluation, Spinal Fluid
Specimen Required
Supplies:
Alzheimer's Disease Evaluation (ADEVL) Collection Kit (T836)
CSF AD Biomarker Tubes (T833; also included in T836)
Container/Tube:
Preferred: Sarstedt CSF False Bottom Tube 63.614.625 (2.5 mL)
Acceptable: Sarstedt 72.703.600 (1.5 mL) or Sarstedt 72.694.600 (2 mL)
Specimen Volume: 1.5 to 2.5 mL
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. For more information see Cautions.
*The Alzheimer's Association consensus protocol for handling of CSF for clinical measurements of Abeta42 and tau recommends using the drip method for CSF collection and directly collecting into a low-bind polypropylene tube. Although some clinicians prefer the syringe pull method due to speed of collection, the drip method reduces the risk of Abeta42 binding to the plastic of any syringe used.
4. Collection instructions can also be found on Spinal Fluid Specimen Collection Instructions for Alzheimer Disease Evaluation (T967).
Useful For
Assessment of adults with cognitive impairment being evaluated for Alzheimer disease and other causes of cognitive impairment
These assays should not be used to predict the development of dementia or other neurologic conditions or to monitor response to therapies.
Method Name
Electrochemiluminescent Immunoassay (ECLIA)
Reporting Name
Alzheimer's Disease Evaluation, CSFSpecimen Type
CSFSpecimen Minimum Volume
See Specimen Required
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| CSF | Refrigerated (preferred) | 14 days | BlueTop SARSTEDT |
| Frozen | 60 days | BlueTop SARSTEDT | |
| Ambient | 12 hours | BlueTop SARSTEDT |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | OK |
| Gross icterus | Reject |
Reference Values
Beta-amyloid (1-42) (Abeta42): >834 pg/mL
Total-Tau: ≤238 pg/mL
Phosphorylated-Tau 181: ≤21.6 pg/mL
p-Tau/Abeta42: ≤0.028
Method Description
Beta-amyloid (1-42):
The Roche cobas assay for determining beta-amyloid (1-42) in cerebrospinal fluid (CSF) uses a sandwich assay principle. A biotinylated monoclonal beta-amyloid (1-42) antibody and a monoclonal beta-amyloid (1-42) specific antibody labeled with a ruthenium complex react to form a sandwich complex. Streptavidin-coated microparticles are added, and the interaction between biotin and streptavidin allows the complex to become bound to the solid phase. The reaction mixture is then aspirated into the measuring cell, microparticles are captured onto the electrode, and the application of voltage induces chemiluminescent emission, which is measured by a photomultiplier.(Package insert: Elecsys beta-Amyloid (1-42) CSF II. Roche Diagnostics; Version 1.0, 12/2022)
Total-Tau:
The Roche cobas assay for determining total-Tau in CSF uses a sandwich assay principle. Two biotinylated monoclonal Tau-specific antibodies and a monoclonal Tau-specific antibody labeled with a ruthenium complex react to form a sandwich complex. Streptavidin-coated microparticles are added, and the interaction between biotin and streptavidin allows the complex to become bound to the solid phase. The reaction mixture is then aspirated into the measuring cell, microparticles are captured onto the electrode, and the application of voltage induces chemiluminescent emission, which is measured by a photomultiplier.(Package insert: Elecsys Total-Tau CSF. Roche Diagnostics; Version 2.0, 10/2023)
Phospho-Tau:
The Roche cobas assay for determining phospho-Tau in CSF uses a sandwich assay principle. A biotinylated monoclonal antibody specific for phosphorylation at threonine 181 and a monoclonal Tau-specific antibody labeled with a ruthenium complex react to form a sandwich complex. Streptavidin-coated microparticles are added, and the interaction between biotin and streptavidin allows the complex to become bound to the solid phase. The reaction mixture is then aspirated into the measuring cell, microparticles are captured onto the electrode, and the application of voltage induces chemiluminescent emission, which is measured by a photomultiplier.(Package insert: Elecsys Phospho-Tau (181P) CSF. Roche Diagnostics; Version 1.0, 12/2022)
Day(s) Performed
Tuesday, Thursday, Friday
Performing Laboratory
Mayo Clinic Laboratories in Rochester
CPT Code Information
83520 x 3
Forms
If not ordering electronically, complete, print, and send a Neurology Specialty Testing Client Test Request (T732) with the specimen.