Test ID THIO Thiopurine Metabolites, Whole Blood
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 determined of thiopurine metabolite values by liquid chromatography-tandem mass spectrometry. Values are utilized to calculate and report a final result (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.
Method Name
Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Reporting Name
Thiopurine Metabolites, BSpecimen Type
Whole Blood EDTASpecimen Minimum Volume
1.5 mL
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Whole Blood EDTA | Refrigerated (preferred) | 8 days | |
Ambient | 24 hours |
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 through Friday
Report Available
2 to 4 daysPerforming Laboratory

Test Classification
This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
80299LOINC Code Information
Test ID | Test Order Name | Order LOINC Value |
---|---|---|
THIO | Thiopurine Metabolites, B | 82869-9 |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
49580 | 6-Thioguanine Nucleotides | 32660-3 |
49581 | 6-Methylmercaptopurine | 32654-6 |
Forms
If not ordering electronically, complete, print, and send Gastroenterology and Hepatology Client Test Request (T728) with the specimen