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Specimen Collection Manual and Test Catalog

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CORTICOSTEROID BINDING GLOBULIN (CBG)

Geisinger Epic Procedure Code:  LAB1337    Geisinger Epic ID:  53273

SPECIMEN COLLECTION
Specimen type: 

Serum


Preferred collection container: 
Alternate collection container: 
6 mL red-top (plain, non-serum separator) tube
Specimen required: 

1 mL serum; minimum 0.5 mL.



SPECIMEN PROCESSING
Processing instructions: 

Centrifuge and aliquot.


Transport temperature: 

Frozen.


Specimen stability: 

Room temperature: 4 hours. Refrigerated: 24 hours. Frozen: 30 days.


Rejection criteria: 

Received room temperature • Gross hemolysis



TEST DETAILS
Additional information: 

This test was developed and its analytical performance characteristics have been determined by Pan Laboratories, Irvine, CA. This assay has been validated pursuant to the CLIA regulations. It has not been cleared or approved by the U.S. Food and Drug Administration.


CPT code(s):  84449
Note: The billing party has sole responsibility for CPT coding.  Any questions regarding coding should be directed to the payer being billed.
The CPT codes provided by GML are based on AMA guidelines and are for informational purposes only.

Methodology: 
Immunoassay
Synonyms: 

Quest test code 92590, Corticostero


Clinical significance: 

Corticosteroid binding globulin (CBG) is a serum alpha 2 globulin-binding protein with high affinity binding for cortisol. Cortisol binds to CBG approximately 92 % of blood levels and rest of the cortisol is as free or bound to serum albumin. CBG is synthesized in liver. The level of CBG is increased during pregnancy and individuals taking contraceptive pills. Elevated levels are also observed in acute hepatitis and in inherited abnormality. Insulin inhibits the synthesis of CBG. The serum level of CBG is lower in hyper-insulinemic status, as in diabetes, PCO and obesity. Severe liver disease and malnutrition may result in low level of CBG. Quantitation of CBG in serum may be useful in assessing unexpected levels of cortisol in serum.


Review Date:  12/11/2024

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