Beta Amyloid 42/40 Ratio, Plasma
Also known as: 42/40 ratio, Alzheimer's lab test, B-Amyloid
Use
The plasma A42/40 ratio is intended for use as an adjunct to diagnostic evaluations of Alzheimer's disease, including neurological and cognitive performance examinations and PET neuroimaging.
Special Instructions
Not provided.
Limitations
Samples that contain fibrin, red blood cells and other insoluble objects may lead to inaccurate results. This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.
Methodology
Immunoassay (CLIA)
Biomarkers
Beta-amyloid 40
AnalyteBeta-amyloid 42
AnalyteBeta-amyloid 42/40 Ratio
Analyte
LOINC Codes
- 106941-8 - Abeta42/ABeta40 Plas LC/MS/MS
- 33200-7 - AL beta42 Plas-mCnc
- 70073-2 - AL beta40 Plas-mCnc
Result Turnaround Time
5 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
2 mL
Minimum Volume
1 mL
Container
Lavender-top (EDTA) tube
Collection Instructions
Draw full lavender-top (EDTA) tube of blood. Separate plasma from blood via centrifugation (>1500g for 10 minutes) within 40 minutes after blood collection. Transfer plasma to Labcorp polypropylene transport tube and seal.
Storage Instructions
Plasma sample may be stored for up to 24 hours at < -10°C (standard freezer) prior to placing in dry ice for shipment, or samples may be stored in the refrigerator for up to 10 hours but then must be placed on dry ice for transport. All samples must be placed on dry ice for transport and must be maintained on dry ice or similar temperatures when reaching the local lab.
Causes for Rejection
Hemolysis; lipemia; heat-treated specimen; gross bacterial contamination; wrong tube type; not stored at proper temperature
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 4 hours |
| Refrigerated | 10 hours |
| Frozen | -10°C: 24 hours; < -60°C: 100 days |
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