Update Type: Reference range changed
Test Updated: 05/10/2023
Test Overview
Test Methodology

Electrochemiluminescent Immunoassay

Test Usage

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.

Reference Range *

Beta-amyloid (1-42) (Abeta42): >1026 pg/mL; Total-Tau: < or =238 pg/mL; Phosphorylated-Tau 181: < or =21.7 pg/mL; p-Tau/Abeta42: < or =0.023

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Details
Days Set Up
Tuesday, Thursday
Analytic Time

2 - 8 days

Soft Order Code
Reference Laboratory
Special Testing
Specimen Requirements
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.
Send to Specimen Processing refrigerated

Special Handling

Test must be collected using the Mayo collection kit, or a polypropylene aliquot tube as a last resort. The conical, screw capped tube form the LP kit IS acceptable to send to Mayo.

Alternate Specimen
Mayo aliquot tube with a blue screw cap and blue writing on it
Normal Volume
1.5 - 2 mL CSF
Minimum Volume
1.5 mL CSF
Storage Temperature
Refrigerated preferred, frozen acceptable
Rejection Criteria
CSF collected in a polystyrene tube (in the LP kit used here at Michigan Medicine), gross hemolysis, lipemia or icterus
Additional Information

Test performed by Mayo Clinic Laboratories

CPT Code
83520 x3