Once you have
ordered your ToxNav test

The below schematic outlines the processes which take place after you place an order


  • Patients offered fluoropyrimidine chemotherapy
  • ToxNav test requested by clinician

  • Blood sample taken (EDTA)
  • Sample requisition form and blood sample sent to laboratory

  • Sample and requisition form received and logged by laboratory
  • DNA extracted

  • Sanger sequencing carried out to detect genotype of 20 variants
  • Data managed via secure server

  • Results transmitted from lab to OCB analysis suite
  • Data imported to ToxNav software
Phenotype (genotype) Implications for treatment Dosing recommendations
Homozygous for wild-type allele, or normal, high DPYD activity Normal DPYD activity 'normal" risk for toxicity Use label-recommended dosage and administration
Heterozygous, or intermediate activity Decreased DPYD activity increased risk for severe or even fatal drug toxicity Start with at least a 50% dose reduction, followed by titration of dose based on toxicity cr pharmacokinetic test
Homozygous, or deficient activity Complete DPYD deficiency increased risk for severe or even fatal drug toxicity Select alternative drug

  • ToxNav Report received by clinician and risk category discussed with patient
  • Personalised chemotherapy decision made