Contents

Search

thiopurine methyltransferase in erythrocytes

Indications: - assessment of likelihood of adverse drug reaction (toxicity) from azathioprine or 6-mercaptopurine [2] Clinical significance: - low thiopurine methyltransferase activity increases likelihood of bone marrow toxicity from azathioprine [2,4] or 6-mercaptopurine [2] - prevalence by phenotype - low activity: 0.3%* - intermediate: 10% - normal activity: 90% - see ref [1] for genotypes Laboratory: - see ARUP consult [1], CPIC guideline [4]

Related

thiopurine S-methyltransferase; thiopurine methyltransferase (TPMT)

General

thiopurine methyltransferase measurement

References

  1. ARUP Consult: Thiopurine Drug Therapy https://arupconsult.com/ati/thiopurine-drug-therapy
  2. Medical Knowledge Self Assessment Program (MKSAP) 17, 18 American College of Physicians, Philadelphia 2015, 2018.
  3. TPMT Lab Tests Online: tpmt
  4. Clinical Pharmacogenetics Implementation Consortium (CPIC) guideline information for azathioprine and TPMT. https://www.pharmgkb.org/guideline/PA166104933