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Pharmacogenetics
(PGx) Testing

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Pharmacogenetics (PGx), an important part of precision medicine, is the study of how genetic variability influences drug treatment outcomes. Recommended by Guidelines, many medications currently prescribed have pharmacogenetic data to support appropriate dosing or selection. Like all diagnostic tests, pharmacotherapeutic genotyping is one of multiple pieces of information that clinicians should consider when making their therapeutic choice for each patient. 

Physicians may order pharmacogenetic testing at the time of drug prescribing and dispensing for patients with genotypes that require action, such as dose reductions. The preemptive use of testing could significantly optimise drug outcomes and be particularly useful for patients undergoing multiple treatments or experiencing poor drug responses. 

  • Pharmacogenetic (PGx) testing at Australian Clinical Labs 

    Clinical Labs offers an extensive range of pharmacogenetic testing panels to provide clinicians and healthcare providers with important information to help determine the most appropriate treatment for each individual, particularly in areas such as mental health, pain management, cardiology and oncology. Our comprehensive pharmacogenetic tests can detect polymorphisms in genes coding for drug metabolising enzymes that predispose individuals to metabolising drugs inadequately.  

    For more information, click on some of our most frequently ordered tests below, or click the button below to view a reference guide for list of genes tested and examples of drugs metabolised. 

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  • Clinical Labs’ Comprehensive PGx Gene Panel 
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    CYP2D6 CYP3A5 CYP2C9 CYP1A2 
    CYP2C19 SLCO1B1 CYP3A4 VKORC1
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     A family of enzymes catalyses the metabolism of many drugs and xenobiotics. For example, CYP2D6, CYP2C19, CYP2C9, and SLCO1B1 variants are responsible for the metabolism of a large number of commonly prescribed medications, including warfarin, analgesics, clopidogrel, codeine, tamoxifen, some antidepressants, statins, proton pump inhibitors (PPIs) and anti-emetics. 

    With the Comprehensive PGx Gene Panel you will receive a comprehensive report that will indicate the genotype and the predicted phenotypes, such as the metaboliser status along with potential drug-gene interaction and guidelines’ recommendations. Please specify any medications of interest if you want them to be included in the report. The genes can be ordered separately or together. For individual genes, only genotyping/phenotyping will be reported.    

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    How to Order Comprehensive Pharmacogenetic (PGx) Testing

    When to Order:

    • Before commencing therapy, or in cases of adverse reaction or resistance.

    Please note: depending on the PGx panel(s) ordered, testing may be performed and reported in collaboration with an external provider.

    Request Form Instructions:

    • Fill out our routine Clinical Labs testing request form. List the gene(s) or group of genes required, and prescribed medications if available. For referrers in WA, click here for our WA Request Form.

    • Patients can visit any of our convenient locations for their blood test. For locations, please visit our Locations page.

    Specimens Details:

    • 2x EDTA blood samples.

    Turnaround Time:

    • Results will be available 2-3 weeks after the sample receipt date.

    Test Cost:

    • No Medicare rebate. An out-of-pocket fee of $190 applies.

    • Note: If any of the genes from the Comprehensive PGx Panel are ordered individually, an out-of-pocket fee of $140 applies, for each gene ordered.

    Additional Resources:

  • Statins Predictor: SLCO1B1 

    SLCO1B1 gene testing is clinically important in clearance of statins, especially simvastatin. Myopathy is reported in poor metabolisers of this gene. Alternative lipid lowering statins can be prescribed in lower doses such as atorvastatin, pravastatin and rosuvastatin (Ramsey et al. 2014). 

    How to order Statins Predictor (SLCO1B1)

    When to order:

    • Before commencing therapy, or in cases of adverse reaction or resistance.

    Please note:

    • Depending on the PGx panel(s) ordered, testing may be performed and reported in collaboration with an external provider.

    Request Form Instructions:

    • Fill out our routine Clinical Labs testing request form. List the gene(s) or group of genes required, and prescribed medications if available. For referrers in WA, click here for our WA Request Form.

    • Patients can visit any of our convenient locations for their blood test. For locations, please visit our Locations page.

    Specimens required:

    • 2x EDTA blood samples.

    Turnaround time:

    • Results will be available 2-3 weeks after the sample receipt date.

    Test cost:

    • No Medicare rebate available. An out-of-pocket fee of $140 applies.

  • Warfarin Panel: CYP2C9 and VKORC1 

    Warfarin is one of the most commonly prescribed medications worldwide, used for many indications including prophylaxis and treatment of thromboembolic disorders, atrial fibrillation, or cardiac valve replacement and systemic embolism after myocardial infarction (MI). While CYP2C9 is predominantly involved in the metabolism of warfarin subtypes; VKORC1 is the molecular target of the drug.  

    How to order Warfarin Predictor (CYP2C9 and VKORC1)

    When to order:

    • Before commencing therapy, or in cases of adverse reaction or resistance.

    Please note:

    • Depending on the PGx panel(s) ordered, testing may be performed and reported in collaboration with an external provider.

    Request Form Instructions:

    • Fill out our routine Clinical Labs testing request form. List the gene(s) or group of genes required, and prescribed medications if available. For referrers in WA, click here for our WA Request Form.

    • Patients can visit any of our convenient locations for their blood test. For locations, please visit our Locations page.

    Specimens required:

    • 2x EDTA blood samples.

    Turnaround time:

    • Results will be available 2-3 weeks after the sample receipt date.

    Test cost:

    • No Medicare rebate available. An out-of-pocket fee of $150 applies.

  • Anti-Depressants Predictor: CYP2D6 and CYP2C19 

    CYP2D6 is the primary enzyme responsible for the metabolism of many commonly-used medications especially in mental health. CYP2D6 alleles have been extensively studied in multiple geographically, racially, and ethnically diverse groups, and significant differences in allele frequencies have been observed.  When considering antidepressant therapy such as tricyclic anti-depressants (TCAs), analysis of the CYP2C19 and CYP2D6 genes is often considered (Attia et al. 2014 and Hicks et al. 2017). 

    How to order Anti-Depressants Predictor (CYP2D6 and CYP2C19)

    When to order:

    • Before commencing therapy, or in cases of adverse reaction or resistance.

    Please note: depending on the PGx panel(s) ordered, testing may be performed and reported in collaboration with an external provider.

    Request Form Instructions:

    • Fill out our routine Clinical Labs testing request form. List the gene(s) or group of genes required, and prescribed medications if available. For referrers in WA, click here for our WA Request Form.

    • Patients can visit any of our convenient locations for their blood test. For locations, please visit our Locations page.

    Specimens Required:

    • 2x EDTA blood samples.

    Turnaround Time:

    • Results will be available 2-3 weeks after the sample receipt date.

    Test Cost:

    • No Medicare rebate available. An out-of-pocket fee of $150 applies.

  • Anti-Psychotics Predictor: CYP2D6 

    CYP2D6 is the primary enzyme responsible for the metabolism of many commonly-used medications especially in mental health. CYP2D6 alleles have been extensively studied in multiple geographically, racially, and ethnically diverse groups and significant differences in allele frequencies have been observed. 

    How to order Anti-Psychotics Predictor (CYP2D6)

    When to Order:

    • Before commencing therapy, or in cases of adverse reaction or resistance.

    Please note:

    • Depending on the PGx panel(s) ordered, testing may be performed and reported in collaboration with an external provider.

    Request Form Instructions:

    • Fill out our routine Clinical Labs testing request form. List the gene(s) or group of genes required, and prescribed medications if available. For referrers in WA, click here for our WA Request Form.

    • Patients can visit any of our convenient locations for their blood test. For locations, please visit our Locations page.

    Specimens Required:

    • 2x EDTA blood samples.

    Turnaround Time:

    • Results will be available 2-3 weeks after the sample receipt date.

    Test Cost:

    • No Medicare rebate available. An out-of-pocket fee of $140 applies.

  • Proton Pump Inhibitors Panel: CYP2C19 

    The hepatic CYP2C19 enzyme contributes to the metabolism of a large number of clinically relevant drugs including some proton pump inhibitors (PPIs). Like many other CYP450 superfamily members, the CYP2C19 gene is highly polymorphic, with >25 known variant alleles. 

    How to order the Protein Pump Inhibitor Panel (CYP2C19)

    When to Order:

    • Before commencing therapy, or in cases of adverse reaction or resistance.

    Please note:

    • Depending on the PGx panel(s) ordered, testing may be performed and reported in collaboration with an external provider.

    Request Form Instructions:

    • Fill out our routine Clinical Labs testing request form. List the gene(s) or group of genes required, and prescribed medications if available. For referrers in WA, click here for our WA Request Form.

    • Patients can visit any of our convenient locations for their blood test. For locations, please visit our Locations page.

    Specimens Required:

    • 2x EDTA blood samples.

    Turnaround Time:

    • Results will be available 2-3 weeks after the sample receipt date.

    Test Cost:

    • No Medicare rebate available. An out-of-pocket fee of $140 applies.

  • Tamoxifen Predictor: CYP2D6 

    CYP2D6 is the primary enzyme responsible for the metabolism of many commonly-used medications especially oncology (tamoxifen and 5-HT3 receptor antagonists) (Goetz et al. 2018). CYP2D6 is highly polymorphic with over 130 identified allelic variants and sub-variants identified (www.PharmVar.org; CYP2D6 Allele Definition). CYP2D6 alleles have been extensively studied in multiple geographically, racially, and ethnically diverse groups and significant differences in allele frequencies have been observed. 

    How to order Tamoxifen Predictor (CYP2D6)

    When to Order:

    • Before commencing therapy, or in cases of adverse reaction or resistance.

    Please note:

    • Depending on the PGx panel(s) ordered, testing may be performed and reported in collaboration with an external provider.

    Request Form Instructions:

    • Fill out our routine Clinical Labs testing request form. List the gene(s) or group of genes required, and prescribed medications if available. For referrers in WA, click here for our WA Request Form.

    • Patients can visit any of our convenient locations for their blood test. For locations, please visit our Locations page.

    Specimens Required:

    • 2x EDTA blood samples.

    Turnaround Time:

    • Results will be available 2-3 weeks after the sample receipt date.

    Test Cost:

    • No Medicare rebate available. An out-of-pocket fee of $140 applies.

  • Clopidogrel Predictor: CYP2C19 

    The hepatic CYP2C19 enzyme contributes to the metabolism of a large number of clinically relevant drugs such as clopidogrel (Scott et al. 2013). Like many other CYP450 superfamily members, the CYP2C19 gene is highly polymorphic, with >25 known variant alleles. 

    How to order Clopidogrel Predictor (CYP2C19)

    When to Order:

    • Before commencing therapy, or in cases of adverse reaction or resistance.

    Please note:

    • Depending on the PGx panel(s) ordered, testing may be performed and reported in collaboration with an external provider.

    Request Form Instructions:

    • Fill out our routine Clinical Labs testing request form. List the gene(s) or group of genes required, and prescribed medications if available. For referrers in WA, click here for our WA Request Form.

    • Patients can visit any of our convenient locations for their blood test. For locations, please visit our Locations page.

    Specimens Required:

    • 2x EDTA blood samples.

    Turnaround Time:

    • Results will be available 2-3 weeks after the sample receipt date.

    Test Cost:

    • No Medicare rebate available. An out-of-pocket fee of $140 applies.

  • Voriconazole Predictor: CYP2C19 

    The hepatic CYP2C19 enzyme contributes to the metabolism of a large number of clinically relevant drugs including anti-fungal medication (voriconazole) (Moriyama et al. 2017)). Like many other CYP450 superfamily members, the CYP2C19 gene is highly polymorphic, with >25 known variant alleles.  

    How to order Voriconazole Predictor (CYP2C19)

    When to Order:

    • Before commencing therapy, or in cases of adverse reaction or resistance.

    Please note:

    • Depending on the PGx panel(s) ordered, testing may be performed and reported in collaboration with an external provider.

    Request Form Instructions:

    • Fill out our routine Clinical Labs testing request form. List the gene(s) or group of genes required, and prescribed medications if available. For referrers in WA, click here for our WA Request Form.

    • Patients can visit any of our convenient locations for their blood test. For locations, please visit our Locations page.

    Specimens Required:

    • 2x EDTA blood samples.

    Turnaround Time:

    • Results will be available 2-3 weeks after the sample receipt date.

    Test Cost:

    • No Medicare rebate available. An out-of-pocket fee of $140 applies.

  • Organ Transplant (Tacrolimus Immunosuppressant) PGx: CYP3A5 

    CYP3A5 genotype results can be used to guide dosing of tacrolimus in organ transplant patients (Birdwell et al. 2015). 

    How to order Organ Transplant PGx (CYP3A5)

    When to Order:

    • Before commencing therapy, or in cases of adverse reaction or resistance.

    Please note:

    • Depending on the PGx panel(s) ordered, testing may be performed and reported in collaboration with an external provider.

    Request Form Instructions:

    • Fill out our routine Clinical Labs testing request form. List the gene(s) or group of genes required, and prescribed medications if available. For referrers in WA, click here for our WA Request Form.

    • Patients can visit any of our convenient locations for their blood test. For locations, please visit our Locations page.

    Specimens Required:

    • 2x EDTA blood samples.

    Turnaround Time:

    • Results will be available 2-3 weeks after the sample receipt date.

    Test Cost:

    • No Medicare rebate available. An out-of-pocket fee of $140 applies.

  • Single Gene Tests (TPMT, DPYD and UGT1A1) 
    • TPMT: Thiopurine methyltransferase (TPMT) is the primary enzyme responsible for the metabolism of thiopurine drugs (azathioprine, 6-mercaptopurine, and 6-thioguanine). It is recommended that physicians order TPMT genotyping before prescribing thiopurines to avoid bone marrow toxicity and subsequent neutropenia. Medicare rebate available. 
    • DPYD: Mutations in the dihydropyrimidine dehydrogenase gene (DPYD) interfere with the breakdown of chemotherapeutic cancer drugs with structures similar to pyrimidines, such as 5-fluorouracil and capecitabine. As a result, these drugs can accumulate in the body, leading to severe reactions and neurological manifestations due to DPD deficiency.  
    • UGT1A1: UGT1A1 gene polymorphism is associated with toxicity and clinical efficacy of irinotecan-based chemotherapy, which is used in patients with advanced solid tumours, including colorectal and lung cancers. 

    How to order Single Gene Test PGx

    When to Order:

    • Before commencing therapy, or in cases of adverse reaction or resistance.

    Please note:

    • Depending on the PGx panel(s) ordered, testing may be performed and reported in collaboration with an external provider.

    Request Form Instructions:

    • Fill out our routine Clinical Labs testing request form. List the gene(s) or group of genes required, and prescribed medications if available. For referrers in WA, click here for our WA Request Form.

    • Patients can visit any of our convenient locations for their blood test. For locations, please visit our Locations page.

    Specimens Required:

    • 2x EDTA blood samples.

    Turnaround Time:

    • Results will be available 2-3 weeks after the sample receipt date.

    Test Cost:

    • TPMT : Medicare rebate available for eligible patients.

    • DPYD : Medicare rebate available for eligible patients.

    • UGT1A1 : No Medicare rebate available. An out-of-pocket fee of $195 for UG1 test and $95 for GIL test applies.

About the Author

Associate Professor Mirette Saad

Associate Professor Mirette Saad

MBBS(Hons) MD(Hons) MAACB FRCPA PhD

Associate Professor Mirette Saad

MBBS(Hons) MD(Hons) MAACB FRCPA PhD
Location: Clayton (VIC)
Speciality: Chemical Pathology
Areas of Interest:
  • antenatal screening
  • cancer genetics
  • clinical research and medical teaching
  • endocrine
  • fertility testing
  • molecular genetics
  • nipt
  • precision medicine
About

Associate Professor Mirette Saad is a Consultant Chemical Pathologist and the National Director of Molecular Genetics at Australian Clinical Labs. She has a Fellowship with honours in Chemical and Molecular Pathology, with Microbiology sub-speciality, from overseas. A/P Saad received her NHMRC sponsored PhD degree in Cancer Genetics from Melbourne University and Peter MacCallum Cancer Institute. Along with her teaching and research roles, A/P Saad is a registered medical practitioner with AHPRA, a Chemical Pathology Fellow (FRCPA) at the Royal College of Pathologists of Australasia and a Member of the Australasian Association of Clinical Biochemists (MAACB). She is a Chair of the RCPA Chemical Pathology Advisory Committee, Member of the RCPA Genetic Advisory Committee, AACB and a Chair of the Precision Medicine Services at Australian Clinical Labs. At Clinical Labs, A/Prof Mirette Saad leads the Molecular Genetic testing for NIPT, antenatal screening, personalised drug therapy and cancer.

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