Sign in →

Test Code Epic LAB3736 Alzheimer Disease Evaluation, Spinal Fluid

Additional Codes

Sunquest order code: ADEVLM


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).


Secondary ID

607273

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, CSF

Specimen Type

CSF

Specimen 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

Report Available

1 to 4 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

83520 x 3

LOINC Code Information

Test ID Test Order Name Order LOINC Value
ADEVL Alzheimer's Disease Evaluation, CSF 104134-2

 

Result ID Test Result Name Result LOINC Value
PTABR p-Tau/Abeta42 41027-4
ADINT AD Interpretation 69048-7
AB42P Abeta42 33203-1
TTAUP Total-Tau 30160-6
PTAUP Phospho-Tau(181P) 72260-3

Forms

If not ordering electronically, complete, print, and send a Neurology Specialty Testing Client Test Request (T732) with the specimen.