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Test Code LAB10027 Thiopurine Metabolites, Whole Blood


Ordering Guidance


This specimen cannot be shared with testing for tacrolimus, cyclosporine, sirolimus or everolimus. Testing for these must be ordered separately and separate specimens submitted.



Shipping Instructions


Specimen must be shipped refrigerated.



Specimen Required


Container/Tube: Lavender top (EDTA)

Specimen Volume: 3 mL

Collection Instructions: Send whole blood specimen in original tube. Do not aliquot, centrifuge, or freeze.


Useful For

Aids physicians in dose adjustments, minimizing dose-dependent toxicity, and monitoring compliance of thiopurine drug therapy

Testing Algorithm

A red blood cell (RBC) count is performed followed by determination of thiopurine metabolite values by liquid chromatography tandem mass spectrometry. Values are utilized to calculate and report the final results (unit of measure: pmol/8 x 10[8] RBC) for 6-thioguanine nucleotides and 6-methylmercaptopurine derivative analyte.

 

For more information see:

-Ulcerative Colitis and Crohn Disease Therapeutic Drug Monitoring Algorithm

-TPMT Testing in the Treatment of Inflammatory Bowel Disease Algorithm

Method Name

Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)

Specimen Type

Whole Blood EDTA

Specimen Minimum Volume

1.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Whole Blood EDTA Refrigerated (preferred) 8 days
  Ambient  24 hours

Reject Due To

Gross hemolysis Reject
Moderate hemolysis Reject
Gross lipemia OK
Gross icterus OK
Clotted Reject

Reference Values

6-Thioguanine Nucleotides (6-TGN): 235-450 pmol/8x10(8) red blood cell (RBC)

6-Methylmercaptopurine (6-MMP): Less than or equal to 5700 pmol/8x10(8) RBC

Day(s) Performed

Monday, Wednesday, Friday

Report Available

2 to 4 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

80299

Forms

If not ordering electronically, complete, print, and send Gastroenterology and Hepatology Test Request (T728) with the specimen