Creating a TB Lab Verification Plan for a New Molecular Platform
The transition from conventional smear microscopy to nucleic acid amplification testing has reshaped tuberculosis diagnostics, and laboratories across Australia are progressively adopting rapid molecular platforms to meet clinical and public health expectations. Whether introducing a GeneXpert, Truenat, Abbott m2000, or another closed-system cartridge-based assay, every site must demonstrate that the platform performs as intended within its own environment before routine patient testing begins. Method verification is the formal process that generates this evidence and bridges the gap between manufacturer claims and local performance.
In Australia, this work is shaped by the National Pathology Accreditation Advisory Council (NPAAC) standards, the National Association of Testing Authorities (NATA) accreditation framework, and Therapeutic Goods Administration (TGA) requirements for in vitro diagnostic devices. Reference laboratories in Sydney, Melbourne, Brisbane, Perth, and Adelaide typically coordinate verification studies, while regional and remote sites often partner with public health laboratories in Darwin or Townsville to access reference material. Planning carefully from the start reduces rework, supports accreditation assessments, and protects patients.
Understanding Method Verification and Regulatory Foundations
Verification confirms that a method already validated by the manufacturer performs acceptably in the user's own laboratory, while validation is the more extensive process of establishing performance characteristics from first principles. For most Australian TB laboratories adopting a TGA-registered molecular platform, verification is the appropriate route because the manufacturer has already submitted validation data to the regulator. The laboratory is still responsible, however, for demonstrating that local conditions, staff competency, sample types, and workflow produce reliable results.
Technical expectations are drawn from international standards such as CLSI EP15-A3 and ISO 15189, both of which underpin NPAAC's Requirements for Medical Pathology Services. The laboratory must define acceptable performance for accuracy, precision, analytical sensitivity, analytical specificity, and reportable range, then design experiments to challenge each parameter. Australian laboratories frequently consult the Royal College of Pathologists of Australasia (RCPA) for guidance on acceptable sample numbers and statistical approaches, particularly when verification falls outside the manufacturer's instructions.
Preparing Personnel, Facilities, and Safety Controls
A verification plan is only as strong as the team that executes it. Before the first specimen is tested, supervisors should confirm that all operators have completed platform-specific training, including module loading, cartridge preparation, result interpretation, and error code recognition. Competency assessment must be documented for each staff member, with refresher sessions scheduled annually or whenever a significant procedural change occurs. Australia's National Tuberculosis Advisory Committee (NTAC) emphasises sustained competency in molecular testing because errors can directly affect treatment initiation and contact tracing.
The physical environment must also be ready. Molecular work requires unidirectional workflow to prevent amplicon contamination, and Australian facilities typically follow PC2 laboratory standards with defined pre- and post-PCR areas. Equipment qualification, including temperature monitoring, biosafety cabinet certification, and uninterrupted power supply checks, should be completed before the study begins. Personal protective practices, particularly glove use protocols, are documented and audited as part of routine quality assurance, reinforcing both biosafety and result integrity.
Designing the Verification Protocol
Protocol design begins with the performance claims the laboratory wishes to verify. Most Australian laboratories focus on concordance with a reference standard, limit of detection across relevant Mycobacterium tuberculosis complex concentrations, and the rate of invalid or error results when testing clinical specimens. A practical sample size is often 30 to 100 positive specimens, supplemented by 50 or more negatives, although smaller studies may be acceptable for low-throughput sites when justified by risk assessment.
Specimens can be sourced from residual archived material with known results or collected prospectively alongside routine testing, provided ethics and patient consent requirements are addressed. For laboratories in remote areas, partnering with a metropolitan reference centre such as the Institute of Clinical Pathology and Medical Research in Sydney or the Victorian Infectious Diseases Reference Laboratory can provide access to well-characterised panels. Quality control materials, including manufacturer-provided controls and any external proficiency testing material, must be run within each batch. The verification plan should also describe how the new platform will fit alongside existing quality assurance practices, such as a stained smear program that remains relevant for phenotypic confirmation.
Executing Testing, Analysing Results, and Documenting Findings
During execution, every run is recorded with date, operator, instrument serial number, kit lot, control results, and specimen identifiers. Deviations, invalid results, and equipment alarms are documented in real time rather than reconstructed later, and each event is investigated before results are released. Statistical analysis compares observed performance against pre-defined acceptance criteria, using methods such as proportion of agreement, Cohen's kappa, or Deming regression when quantitative outputs are available.
If acceptance criteria are not met, the laboratory must investigate root causes, repeat testing, and revise the plan if necessary. Approval to implement the platform in routine service is granted only when results satisfy the documented criteria, and a verification report is signed by the laboratory director or designee. This report becomes part of the laboratory's accreditation evidence and is reviewed during NATA assessments. Ongoing performance is monitored through internal quality control, external proficiency testing such as the RCPA Quality Assurance Program, and periodic re-verification when reagent lots, instruments, or protocols change. A practical way to keep these activities on track is to maintain a visual maintenance calendar that plots verification milestones, maintenance tasks, and re-verification due dates in one place.
Performance Characteristics and Their Acceptance Considerations
| Performance characteristic | What it measures | Typical verification approach | Common acceptance criteria |
|---|---|---|---|
| Accuracy/agreement | Concordance with reference method or expected result | Test 30–100 positive and 50+ negative specimens | ≥95% overall agreement; investigate discordants |
| Precision (reproducibility) | Variability between runs, operators, instruments | Repeat testing across days, operators, and modules | Coefficient of variation within manufacturer claims |
| Analytical sensitivity | Lowest concentration reliably detected | Test serial dilutions of quantified reference material | Detects manufacturer-claimed limit of detection |
| Analytical specificity | Ability to distinguish target from near-neighbours | Test non-tuberculous mycobacteria and negative samples | No false positives; cross-reactivity documented |
| Reportable range | Spectrum of results the assay can reliably produce | Evaluate across expected clinical concentrations | Results within validated range accepted without dilution |
| Invalid/error rate | Proportion of runs failing internal controls | Track across at least 100 clinical specimens | Below locally defined threshold, typically <5% |
A well-structured verification report captures experimental conditions, raw data, statistical outputs, deviations, and corrective actions in a single, traceable record. Many Australian laboratories store this report within their quality management system alongside SOPs, training records, and instrument qualification files, allowing assessors to reconstruct the entire verification history during a NATA audit.
Practical Recommendations for a Strong Verification Plan
- Engage the NATA-accredited reference laboratory network early to source well-characterised specimens and avoid delays.
- Map each performance claim from the manufacturer's package insert to a specific test in your protocol so no claim is overlooked.
- Include at least one external quality control material in every run, in addition to the kit controls, to strengthen accreditation evidence.
- Predefine the statistical method, sample size, and acceptance limits in a written protocol signed off before testing begins.
- Plan for re-verification triggers, such as new reagent lots, software upgrades, or staff changes, and document them in the quality manual.
- Involve the laboratory director, senior scientists, and the quality manager in the final review so that implementation approval is clearly authorised.
- Use the GLI Quality Tool checklists to align your verification activities with the twelve Quality Systems Essentials and phase-specific guidance.
When the verification report is complete, integrate the new platform into routine service with updated standard operating procedures, staff training records, and patient result reporting pathways. Notify clinicians about the change in methodology, expected turnaround times, and any limitations identified during the study. Continue to monitor performance through monthly quality indicators, and revisit the verification plan whenever the laboratory introduces a new assay version, expands testing volume, or relocates equipment. By treating verification as a living component of the quality management system rather than a one-off exercise, Australian TB laboratories can confidently adopt new molecular technologies while meeting national and international expectations for reliable, patient-centred diagnostics. Start building your verification framework today using the GLI Quality Tool resources and download the phase-specific checklists to support each step of the process.