Beta-Amyloid 42/40 Ratio, CSF

Test Code
94627


CPT Codes
82233, 82234

Includes
ABeta 42, ABeta 40, and ABeta 42/40 Ratio


Preferred Specimen
0.5 mL CSF collected in polypropylene tube


Minimum Volume
0.3 mL


Instructions

Collect and transport CSF in a polypropylene tube. Store frozen.

Note: Quest Diagnostics does not perform this test for individuals under the age of 18. Pre-test and post-test counseling is strongly recommended.



Transport Container
Polypropylene tube


Transport Temperature
Frozen


Specimen Stability
Room temperature: 72 hours
Refrigerated: 5 days
Frozen: 31 days


Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Hemolysis • Icterus • Lipemia • Specimens collected in a glass, polystyrene, or polycarbonate tube


Methodology
Liquid Chromatography/Tandem Mass Spectrometry (LC/MS/MS)

FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule
Set up: Sun; Report available: 4-11 days


Reference Range
ABeta 42No Reference Range available
ABeta 40No Reference Range available
ABeta 42/40 Ratio
≥0.16Low Risk of Alzheimer's disease
<0.16Increased risk of Alzheimer's disease


Clinical Significance
This LC-MS/MS assay measures beta-amyloid 40 (AB40) as well as AB42 in cerebrospinal fluid (CSF), rather than AB42 alone. This permits the normalization of beta amyloid levels circulating in CSF in different patients. Using the ratio of beta-amyloid 42/beta-amyloid 40, improves sensitivity and specificity for detecting Alzheimer's disease.


Performing Laboratory
Quest Diagnostics Nichols Institute-San Juan Capistrano, CA
33608 Ortega Highway
San Juan Capistrano, CA 92675-2042




The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.