Amyloid Beta 42/40 Ratio
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Beta-Amyloid 42/40 Peptide Ratio, CSF
Test ID: BARATIO SF
Test
Aliases/Synonyms
Method
LC-MS/MS
Method Description
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.
Report Includes
Amyloid beta peptide 42; Amyloid beta peptide 40; Amyloid beta peptide 42/40 Ratio
Specimens
CSF
Clinical Utility
Quest Diagnostics does not perform this test for individuals under the age of 18. Pre-test and post-test counseling is strongly recommended.
Test Location
Quest Diagnostics, California USA
Test Version
5-May-2021
Specimen
Specimens
CSF
Sample Volume
1.2 mL
Minimum Volume
0.6 mL
Specimen Comment
Quest Diagnostics does not perform this test for individuals under the age of 18. Pre-test and post-test counseling is strongly recommended.
Collection & Handling
Collection Instructions
Do not use glass, polystyrene or polycarbonate tubes.
Handling Information
Do not collect or transfer in a glass, polystyrene, or polycarbonate tube.
Store and send frozen.
Stability
| Ambient | 72 hours |
|---|---|
| Refrigerated | 5 days |
| Frozen | 31 days |
Rejection Criteria
| Age | Under 18 |
|---|---|
| Hemolysis | Moderate or gross |
| Lipemia | Gross |
| Specimen | Collected in a glass, polystyrene, or polycarbonate tube |
| Other | Moderately or grossly icteric |
Test Version
5-May-2021
Performance / Interpretation
Method
LC-MS/MS
Method Description
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.
Turnaround Time
15 days
Test Location
Quest Diagnostics, California USA
Test Version
5-May-2021
Interface / Setup
HL7 Interface Codes
| Order Code | Result Codes | Units |
|---|---|---|
| BARATIO SF | 63144ABETA 42 | pg/mL |
| 63145ABETA 40 | pg/mL | |
| 63146ABETA 42/40 RATIO | None |
Test Version
5-May-2021