Geisinger Medical Laboratories/Geisinger Proven Diagnostics Test Catalog

Test Name: Sunquest Test Code Epic Procedure Code Or ID CPT Code:  

THIOPURINE METABOLITES

ORDERING INFORMATION:
Sunquest Test Code:
THIPUR      Geisinger Epic Procedure Code: THIPUR         Geisinger Epic ID: 44147

SPECIMEN COLLECTION
Specimen type:
Whole blood
Preferred collection container:
Alternate Collection Container:
6 mL lavender-top K2 EDTA tube
Specimen required:
5 mL whole blood; minimum 2.5 mL
Special notes:
A trough specimen is required (within 1 hour prior to the next dose).

SPECIMEN PROCESSING
Transport temperature:
Refrigerated
Specimen stability:
5 days
Rejection criteria:
Hemolysis, heparinized whole blood; frozen specimen

TEST DETAILS
Reference interval:
6-TG 235-400 pmol/8x108 RBC
6-MMP <5700 pmol/8x108 RBC
CPT code(s):
80375
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.
Test includes:
6-Thioguanine (6-TG), 6-Methylmercaptopurine (6-MMP)
Methodology:
Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
Synonyms:
6-Methylmercaptopurine (6-MMP),6-MP,6-Thioguanine (6-TG),AZA
Quest test code 91745
Clinical significance:
6-Mercaptopurine (Purinethol) and its imidazolyl derivative, Azathioprine (Imuran), are immunosuppressive drugs. 6-Mercaptopurine (6-MP) is indicated for remission induction and maintenance therapy of acute lymphoblastic leukemia (ALL). Azathioprine is indicated as an adjunct for the prevention of rejection in renal allograft (kidney transplant) patients, for the management of rheumatoid arthritis, and for the management of inflammatory bowel disease. Azathioprine is cleaved to 6-MP. 6-MP is metabolized via a series of enzymatic steps to 6-thioguanine nucleotides (6-TGNs), to 6-methyl-mercaptopurine (6-MMPNs) by the enzyme thiopurine methyltransferase (TPMT), and to 6-thiouric acid by the enzyme xanthine oxidase (XO). TPMT enzyme activity has large inter-individual variations which affect the efficacy, toxicity and variability of the treatment. Therapeutic drug monitoring of 6-MP metabolites (6-TGNs and 6-MMPNs) in erythrocytes is recommended to assist therapy, particularly in combination with TPMT enzyme activity or mutation analysis.

Performing Locations

Quest Diagnostics

Technical Lead: Michael Weaver    
Frequency: Setup Tuesday-Saturday    
Performed stat? No
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