A practical risk assessment for new TB testing methods
Introducing a new tuberculosis testing method can improve diagnostic access, shorten turnaround times, or detect drug resistance more effectively. It can also create hazards if the method is adopted without understanding its effect on specimens, staff, equipment, reporting, and clinical decisions. A structured risk assessment helps a laboratory identify those hazards before routine testing begins.
The assessment should cover the entire testing pathway, from ordering and specimen collection to result interpretation, reporting, storage, and disposal. It should also reflect the laboratory’s actual setting. A method that is safe and reliable in a well-resourced reference laboratory may require different controls in a facility with limited space, unstable electricity, or few trained staff.
The goal is not to prevent innovation. It is to decide whether the method is suitable, what controls are required, and how the laboratory will know that those controls continue to work. Risk assessment should therefore be linked to verification, staff competency, documentation, incident management, and continual improvement.
Define the method and its intended use
Begin by describing the proposed test in precise operational terms. Record the assay or platform, specimen types, target analytes, intended users, testing volume, expected turnaround time, and the clinical or public health decisions supported by the results. State whether the method is for screening, diagnosis, treatment monitoring, or detection of resistance.
The intended use determines the consequences of failure. A false-negative result for pulmonary TB may delay treatment and prolong transmission, while an incorrect rifampicin-resistance result may lead to an unsuitable treatment regimen. Consider the populations served, including children, people living with HIV, patients with extrapulmonary disease, and individuals whose specimens may have low bacillary loads.
Review the manufacturer’s instructions, regulatory status, performance claims, and limitations. Compare those claims with local conditions rather than assuming that published performance will transfer unchanged. Before implementation, laboratory leaders should also review the user instructions so that the assessment aligns with the quality roadmap and its phase-specific activities.
Map the workflow and identify hazards
Create a step-by-step process map covering the pre-examination, examination, and post-examination phases. Include test requesting, patient identification, specimen collection, transport, receipt, rejection, preparation, testing, result review, reporting, referral, and waste management. Mapping often reveals risks outside the instrument itself.
For each step, ask what could go wrong, why it might happen, and what the effect would be. Common hazards include mislabelled specimens, inadequate volume, delayed transport, contamination, incorrect sample inactivation, reagent deterioration, transcription errors, invalid runs, and failure to communicate critical results. Include risks associated with interruptions such as power failure, network downtime, stock-outs, or equipment breakdown.
Assess biosafety separately from analytical performance. Determine whether the method generates aerosols, requires opening tubes, uses chemical hazards, or changes the volume and concentration of infectious material handled at the bench. Review ventilation, biological safety cabinets, personal protective equipment, decontamination procedures, spill response, sharps management, and exposure reporting. A method that reduces hands-on manipulation may lower risk, but that assumption should be demonstrated rather than presumed.
Estimate and prioritize the risks
A simple risk matrix can help a multidisciplinary team rank hazards consistently. Estimate the likelihood that an event will occur and the severity of its consequences. Some laboratories add detectability, meaning how likely the problem is to be identified before it affects a patient or public health decision. Use clear definitions for each rating and document the reasoning behind the score.
The team should include testing staff, the laboratory manager, a biosafety representative, a clinician or TB programme representative, information technology staff when digital reporting is involved, and procurement or maintenance personnel as appropriate. Different perspectives are important because a process that appears controlled at the bench may create a serious problem during specimen transport or result communication.
| Risk area | Typical failure | Possible consequence | Useful control |
|---|---|---|---|
| Specimen quality | Insufficient, unsuitable, or delayed specimen | Invalid or false-negative result | Collection criteria, rejection rules, transport monitoring |
| Analytical process | Incorrect reagent, contamination, or instrument error | Incorrect patient result or repeated testing | Lot checks, controls, maintenance, contamination prevention |
| Biosafety | Aerosol generation or inadequate decontamination | Occupational exposure or environmental release | Engineering controls, PPE, SOPs, incident response |
| Result reporting | Transcription, interface, or interpretation error | Delayed or inappropriate treatment | Result review, validated interface, critical-result procedure |
| Continuity | Power, connectivity, or stock interruption | Service disruption and delayed diagnosis | Backup supplies, contingency workflow, escalation plan |
Prioritize risks that could cause severe patient harm, TB transmission, occupational exposure, or systematic reporting errors. A low-frequency event may still require strong controls when its impact is high. Conversely, avoid treating every minor deviation as a reason to reject the method; the matrix should support proportionate decisions.
Confirm performance before routine use
Risk control depends on evidence that the method works in the intended environment. Verification confirms that an established method performs acceptably in the laboratory’s hands, using its staff, equipment, specimens, and workflow. Validation is generally required when the laboratory modifies a method or develops its own procedure. Define the applicable approach before testing begins.
The evaluation plan should address accuracy or agreement, precision where relevant, analytical sensitivity, specificity, invalid and error rates, interference, carryover, contamination, and result interpretation. For TB assays, include representative positive and negative materials and, where relevant, samples covering different bacillary loads and resistance profiles. Use a reference method, characterized panel, external quality assessment material, or other justified comparator.
Plan how discrepant results will be investigated. A discordant result may reflect specimen heterogeneity, a limitation of the comparator, contamination, incorrect operation, or a genuine difference in detection capability. Record the investigation and the final decision. Do not quietly exclude inconvenient results from the analysis unless there is a documented, scientifically justified reason.
Staff competency is part of method performance. Training should include theory, practical operation, biosafety, quality control, troubleshooting, result interpretation, and documentation. Each user should demonstrate competence before independent testing and at defined intervals afterward. The laboratory should also verify that workload, staffing levels, and supervision are realistic for the proposed service.
Build controls into the quality system
Convert the risk assessment into controlled procedures rather than leaving it as a static report. Update standard operating procedures, forms, worksheets, equipment records, maintenance schedules, quality-control plans, and specimen acceptance criteria. Define who may authorize testing, review results, release reports, investigate deviations, and approve changes.
Information management deserves particular attention. New testing methods often produce electronic results, flags, images, resistance profiles, or quality indicators that must move safely between instruments, laboratory information systems, clinicians, and TB surveillance programmes. Plan user access, data verification, backup, downtime procedures, audit trails, confidentiality, and interface testing. The TB data management guide provides practical context for building these controls.
Include supplier and stock-management risks. Confirm reagent storage conditions, expiry monitoring, lot-to-lot checks, minimum stock levels, calibration requirements, service arrangements, and access to spare parts. If the method depends on a proprietary cartridge or cloud service, document alternatives and escalation routes for supply or connectivity failures.
Monitor the method after implementation
Approval to begin testing is the start of monitoring, not the end of risk management. Establish indicators that can reveal emerging problems. Useful measures include rejection rates, invalid and error rates, repeat testing, turnaround time, contamination events, quality-control failures, amended reports, complaints, stock-outs, equipment downtime, and staff competency results.
Set action limits and define what happens when they are exceeded. A single critical incident may require immediate suspension and investigation, while a gradual increase in invalid results may trigger preventive maintenance, refresher training, environmental review, or supplier contact. Trend data over time because small changes can be more informative than an isolated result.
Review the risk assessment whenever there is a new instrument, reagent lot, specimen type, software update, staffing change, facility modification, incident, or significant change in testing volume. Periodic review should involve the people who perform and use the service. The Phase 1 roadmap can help laboratories organize foundational work involving personnel, equipment, documents, safety, and management responsibility before expanding implementation.
Actions that make the assessment usable
- Assign an owner for every high-priority risk and record a due date for each control.
- Use real local data, including specimen rejection, invalid-result, and turnaround-time records.
- Test contingency procedures through simulations such as power loss, connectivity failure, or instrument downtime.
- Require documented competency assessment before staff perform the method independently.
- Schedule a post-implementation review after the first defined period of routine testing.
A useful risk register should show the original risk, existing controls, residual risk, evidence of effectiveness, and the person responsible for follow-up. Keep the language specific: “verify reagent temperature daily and document excursions” is more actionable than “ensure proper storage.” Link each control to a form, record, observation, or performance indicator that can be checked.
A sound assessment also supports communication with clinicians and programme managers. Explain what the method detects, what it cannot detect, expected reporting times, reasons for invalid results, and when confirmatory testing is required. Clear communication reduces the chance that a technically correct result will be misunderstood or acted on outside its intended purpose.
Use the completed assessment to make a documented implementation decision: proceed, proceed with conditions, defer pending controls, or reject the method for the current setting. Then revisit that decision with evidence from routine service. By connecting hazard identification, performance evaluation, staff readiness, biosafety, information management, and ongoing review, a TB laboratory can introduce new testing with greater confidence and stronger protection for patients, workers, and the wider community.