Beta Amyloid 42/40 Ratio, CSF

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

Related Documents

Specimen Requirements


Cerebrospinal fluid (CSF)


8 mL

Minimum Volume

5 mL


Sarstedt CSF Tube 62.610.018. Tube provided by Labcorp by request.


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



Room temperature

8 hours


8 days


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


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.


This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.


Chemiluminescent enzyme immunoassay (CLEIA)


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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