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TEST ID ADEVL Alzheimer Disease Evaluation, Spinal Fluid

Important Note

Requires special tube at collection.  CSF collected in a regualr plastic tube will be rejected. 

Reporting Name

Alzheimer's Disease Evaluation, CSF

Specimen Type

CSF


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).


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

Method Name

Electrochemiluminescent Immunoassay (ECLIA)

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

Day(s) Performed

Tuesday, Thursday, Friday

Report Available

1 to 4 days

Specimen Retention Time

12 months

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.

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.

Highlights

Measurement of beta-amyloid (1-42)(Abeta42), total Tau, and phosphorylated Tau (p-Tau181) in cerebrospinal fluid is useful in the differential diagnosis of Alzheimer disease (AD) and other causes of cognitive impairment.

 

The p-Tau181/Abeta42 ratio provides excellent concordance with amyloid positron emission tomography (PET) imaging to assess the presence of amyloid deposition in patients with AD.