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Beta-Amyloid 42/40 Ratio, CSF
Test Code94627
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
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 42 | No Reference Range available |
ABeta 40 | No Reference Range available |
ABeta 42/40 Ratio | |
≥0.16 | Low Risk of Alzheimer's disease |
<0.16 | Increased 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 |