How Accurate Is PGx?

Clinicians need confidence that pharmacogenetic testing provides reliable, actionable information. Modern PGx focuses on well-established CYP450 pathways — such as CYP2C19, CYP2D6 and CYP2B6 — enabling prescribers to anticipate how a patient will respond to common medicines.

From a laboratory perspective, genotyping accuracy exceeds 99% for validated variants. The crucial consideration is the strength of evidence supporting each drug–gene interaction.

For example, CYP2C19 poor metabolisers and clopidogrel is a CPIC Level A recommendation and is now referenced by NICE in cardiovascular guidance. Similarly, CYP2D6 testing is clinically relevant when selecting opioids or antidepressants, and SLCO1B1 testing can prevent statin-associated muscle toxicity.

At AttoDiagnostics, only guideline-supported interactions are reported with actionable recommendations, enabling confident prescribing decisions.

Key Takeaways

• Genotyping accuracy for PGx markers is >99%
• Greatest value where CPIC Level A recommendations apply
• NICE now references CYP2C19 genotype testing for clopidogrel
• CYP2D6 and CYP450 insights support antidepressant and analgesic selection
• Improves safety, adherence, and time to treatment stability

Clinical Example: Statin Myopathy Prevention

A 57-year-old patient begins simvastatin for primary prevention and soon experiences muscle pain.?Pharmacogenetic testing identifies an SLCO1B1 decreased-function phenotype, predicting elevated risk of statin-induced myopathy. Switching to rosuvastatin — which is less dependent on this pathway — maintains lipid control without adverse effects.?This supports adherence and reduces cardiovascular event risk.

Frequently Asked Questions

How accurate is the testing?

99% analytical accuracy for validated variants.

Why are some drugs not included?

Only drug–gene pairs with sufficient clinical evidence (e.g., CPIC A/B).

Does PGx replace clinician judgement?

No — it enhances treatment decision-making, especially when response is unpredictable.

Is CYP2D6 and CYP450 testing available in the UK?

Yes — via UK-accredited labs such as AttoDiagnostics.

Who benefits most?

Patients with side effects, poor efficacy or high-risk medications (clopidogrel, simvastatin, SSRIs, codeine).

Related Reading

• Clopidogrel and CYP2C19 — NICE-aligned guidance
• Opioids and CYP2D6 — preventing toxicity or non-response
• Statins and SLCO1B1 — improving adherence
  
  

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See how PGx integrates into your prescribing workflow. Book a Demo with AttoDiagnostics?Our clinical team will walk you through a real case and referral process.