title: Thiopurine S-methyltransferase testing for averting drug toxicity in patients receiving thiopurines: a systematic review.
abstract: Thiopurine S-methyltransferase (TPMT) testing is used in patients receiving thiopurines to identify enzyme deficiencies and risk for adverse drug reactions. It is uncertain whether genotyping is superior to phenotyping. The objectives were to conduct a systematic review of TPMT-test performance studies.
  
  
  
  Electronic and grey literature sources were searched for studies reporting test performance compared with a reference standard. Sixty-six eligible studies were appraised for quality.
  
  
  
  Thirty phenotype-genotype and six phenotype-phenotype comparisons were of high quality. The calculated sensitivity and specificity for genotyping to identify a homozygous mutation ranged from 0.0-100.0% and from 97.8-100.0%, respectively.
  
  
  
  Clinical decision-makers require high-quality evidence of clinical validity and clinical utility of TPMT genotyping to ensure appropriate use in patients.
authors.affiliation: Child Health Evaluative Sciences, The Hospital for Sick Children Research Institute, Toronto, Canada.
authors.forename: Lilla M
authors.initials: LM
authors.lastname: Roy
authors.affiliation: Child Health Evaluative Sciences, The Hospital for Sick Children Research Institute, Toronto, Canada.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Zur
authors.affiliation: Library Services, The Hospital for Sick Children, Toronto, Canada.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Uleryk
authors.affiliation: Institute for Health Policy, Management & Evaluation, University of Toronto, Canada.
authors.forename: Chris
authors.initials: C
authors.lastname: Carew
authors.affiliation: Centre for Genetic Medicine, The Hospital for Sick Children, Toronto, Canada.|Division of Clinical Pharmacology & Toxicology, The Hospital for Sick Children, Toronto, Canada.
authors.forename: Shinya
authors.initials: S
authors.lastname: Ito
authors.affiliation: Child Health Evaluative Sciences, The Hospital for Sick Children Research Institute, Toronto, Canada.|Departments of Pharmacology & Pharmacy, Faculty of Medicine Department of Paediatrics, University of Toronto, Canada.
authors.forename: Wendy J
authors.initials: WJ
authors.lastname: Ungar
mesh_terms: D000293:Adolescent; D000328:Adult; D064420:Drug-Related Side Effects and Adverse Reactions / Q000235:genetics*; D005260:Female; D005820:Genetic Testing / Q000379:methods; D005838:Genotype; D006801:Humans; D008297:Male; D008780:Methyltransferases / Q000235:genetics*; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D012680:Sensitivity and Specificity
chemical_list: D008780:Methyltransferases; C022745:thiopurine methyltransferase
keywords: QUADAS-2; enzyme deficiency; genetic test; phenotype; quality appraisal; sensitivity; specificity; systematic review; thiopurine S-methyltransferase