Webinar: Implementation of an ISO 15189-Accredited Next-Generation Sequencing Service for Cell-free Total Nucleic Acid (cfTNA) Analysis: The Experience of a Clinical Diagnostic Laboratory

Webinar summary

This presentation outlines the implementation of an accredited next-generation sequencing (NGS) service for liquid biopsy testing at Cork University Hospital. The focus is on enabling cell-free total nucleic acid analysis from blood samples to support driver mutation reporting and improve molecular diagnostics in a clinical laboratory setting.

Study overview

The initiative was driven by the need to expand molecular testing capabilities beyond single-gene PCR and external referral workflows, which were associated with long turnaround times and limited tissue availability.

An in-house NGS program was established beginning in 2021, with validation of a 50-gene panel aligned to national guidelines for non-small cell lung cancer (NSCLC). This was followed by a six-month validation and verification process for liquid biopsy testing, achieving ISO 15189 accreditation in 2023.

The assay uses total nucleic acid extraction from plasma to enable both DNA variant detection and fusion analysis. Validation included:

• Real-world clinical samples matched to tissue results
• Commercial reference standards
• External quality control materials

The workflow supports a two-day turnaround, with automated extraction, sequencing, and reporting processes designed to deliver rapid and reliable results for clinical decision-making.

Key findings

Clinical utility of liquid biopsy

• Liquid biopsy enables real-time characterization of cancer using circulating tumor DNA (ctDNA)
• The approach provides diagnostic and prognostic insights while capturing tumor heterogeneity
• Blood-based testing offers a minimally invasive and repeatable alternative to tissue biopsy

Workflow efficiency and turnaround time

• A streamlined two-day workflow was achieved, including sample preparation, sequencing, and reporting
• Automation reduced hands-on laboratory time and supported flexible sample throughput
• Rapid turnaround times improved clinical utility for oncology teams

Performance and concordance

• Validation demonstrated approximately 83% concordance with orthogonal tissue-based methods
• Optimal results achieved with sample input volume of 5 ng TNA
• Quality control metrics were established and applied prior to result reporting

Advantages over previous workflows

• Transition from single-gene PCR to multi-gene NGS expanded biomarker coverage
• Reduced reliance on external laboratories improved turnaround time and patient management
• Blood-based testing addressed challenges related to limited tissue availability

Limitations and considerations

• Liquid biopsy does not provide full tumor pathology or certain biomarkers such as PD-L1
• False negatives may occur in cases of low tumor shedding
• False positives may arise from germline variants

Clinical implementation and use cases

• A plasma-first approach is used when tissue biopsy is not feasible or delayed
• Liquid biopsy is also applied sequentially to monitor treatment response and disease progression
• Reporting focuses on key actionable variants in NSCLC, with structured reports supporting treatment decisions

Conclusion

The implementation of an accredited liquid biopsy NGS service enabled rapid, comprehensive molecular profiling in a clinical diagnostic laboratory. By integrating automated workflows, validated performance metrics, and clinically actionable reporting, the approach improved turnaround times and expanded access to biomarker testing.

This service supports precision oncology through minimally invasive testing, with ongoing plans to extend applications to additional cancer types and longitudinal disease monitoring.

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