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Thiopurine Drug Metabolites (Temporary Referral as of 02/23/17)
2011134
Ordering Recommendation

Optimize therapy for thiopurine drugs. Identify thiopurine metabolite concentrations that may lead to toxicity.

Mnemonic
THIOPMET
Methodology
Quantitative Liquid Chromatography/Tandem Mass Spectrometry
Performed
Tue, Thu, Sun
Reported
1-5 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
Specimen Required
Patient Preparation
 
Collect
Lavender (EDTA), pink (K2EDTA) 
Specimen Preparation
Transport 5 mL whole blood. (Min: 3.5 mL) 
Storage/Transport Temperature
Refrigerated. 
Unacceptable Conditions
Frozen samples, Hemolyzed samples. 
Remarks
 
Stability
Ambient: 72 hours; Refrigerated: 8 days; Frozen: Unacceptable 
Reference Interval
Test Number
Components
Reference Interval
 6-TG Nucleotides RBC230-400 pmol/8 x 108 RBC
 6-MMP Nucleotides RBCLess than 5701 pmol/8 x 108 RBC

Interpretive Data
Concentrations of 6-thioguanine nucleotide (6-TGN) less than 230 pmol/8 x 108 RBC may indicate a reduced response to therapy; 6-TGN concentrations greater than 400 pmol/8 x 108 RBC may indicate a higher risk for leukopenia. Concentrations of 6-methyl mercaptopurine nucleotide (6-MMPN) greater than 5700 pmol/8 x 108 RBC may indicate a higher risk for hepatotoxicity.

Compliance Statement B: This test was developed and its performance characteristics determined by ARUP Laboratories. The U.S. Food and Drug Administration has not approved or cleared this test; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions.

Note
CPT Code(s)
80299 x2 (Alt code: G0480)
Components
Component Test Code*Component Chart NameLOINC
20111386-TG Nucleotides RBC32660-3
20111396-MMP Nucleotides RBC32654-6
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • 6 mercaptopurine
  • TPMT (Thiopurine Drug Metabolites)