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Special Instructions
This test requires a dedicated Sarstedt CSF liquor low protein binding tube sent directly to the testing facility.
Expected Turnaround Time
5 - 8 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Related Documents
Specimen Requirements
Specimen
Cerebrospinal fluid (CSF)
Volume
8 mL
Minimum Volume
5 mL
Container
Sarstedt CSF Tube 62.610.018. Tube provided by Labcorp by request.
Collection
Collect cerebral spinal fluid (CSF) in Sarstedt CSF Tube 62.610.018. Tube must be filled 50% to 80% minimum. Specimen must be collected in Sarstedt tube directly and cannot be transferred from a regular collection tube. If first 1 mL is hemolyzed, discard and continue to draw sample.
Storage Instructions
Refrigerate immediately (preferred), within 8 hours.
Freeze on arrival (at Labcorp).
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | 8 hours |
Refrigerated | 8 days |
Frozen | 30 days |
Freeze/thaw cycles | Stable x1 |
Causes for Rejection
Wrong tube type; not stored at proper temperature; quantity not sufficient; sample transferred from another tube; gross hemolysis
Test Details
Use
To indicate the ratio of beta-amyloid 42 proteins to beta-amyloid 40 proteins measured in the CSF to aid in the assessment of disease progression in patients with suspected or probable Alzheimer's disease.
Limitations
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
Chemiluminescent enzyme immunoassay (CLEIA)
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 505560 | Beta Amyloid 42/40 Ratio, CSF | 98584-6 | 505542 | Beta-amyloid 42 | pg/mL | 33203-1 |
| 505560 | Beta Amyloid 42/40 Ratio, CSF | 98584-6 | 505540 | Beta-amyloid 40 | pg/mL | 70072-4 |
| 505560 | Beta Amyloid 42/40 Ratio, CSF | 98584-6 | 505543 | Beta-amyloid 42/40 | 98485-6 | |
| 505560 | Beta Amyloid 42/40 Ratio, CSF | 98584-6 | 505539 | Interpretation: | N/A | |
| 505560 | Beta Amyloid 42/40 Ratio, CSF | 98584-6 | 505544 | References: | N/A |
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CPT Statement/Profile Statement
The LOINC® codes are copyright © 1994-2021, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee. Permission is granted in perpetuity, without payment of license fees or royalties, to use, copy, or distribute the LOINC® codes for any commercial or non-commercial purpose, subject to the terms under the license agreement found at https://loinc.org/license/. Additional information regarding LOINC® codes can be found at LOINC.org, including the LOINC Manual, which can be downloaded at LOINC.org/downloads/files/LOINCManual.pdf