Beta Amyloid 42/40 Ratio, CSF

TEST: 505560
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CPT: 83520(x2)
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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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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