GLI GLI Quality Tool
GLI Quality Tool — Version 2.0

Retesting TB specimens after malfunction or power outage

Establishing a TB laboratory specimen retesting policy after equipment malfunction or power outage starts with one principle: disruption creates a reason to assess validity, not an automatic reason to repeat every test. Clinical specimens, culture isolates, smears and molecular-test aliquots may experience interrupted processing, temperature excursions, instrument faults or incomplete records. A written decision framework protects patients, preserves evidence and keeps the laboratory consistent with its quality management system.

The policy should identify who may authorise a retest, which results are held, what evidence is required and how reports are communicated. Cover planned faults and sudden outages, including loss of monitoring or alarms. The GLI Quality Tool’s four phases and twelve Quality Systems Essentials provide a useful framework because specimen retesting connects safety, equipment, documentation, assessment and continual improvement.

Australian laboratories need an approach that works across metropolitan and regional settings. Major referral laboratories in Sydney and Melbourne may process high volumes, while services in Perth, Darwin and remote Northern Territory communities face long courier routes, hot conditions and limited on-site engineering support. Electronic requests and scheduled courier rounds are common, but imported reagents and variable freight schedules can reduce the time available to recover samples and finish repeat testing.

Local regulation and accreditation make clear records especially important. In vitro diagnostic devices marketed in Australia are regulated by the Therapeutic Goods Administration under the Therapeutic Goods Act 1989. Biosafety duties arise under the Commonwealth Biosafety Act 1989 and relevant state or territory legislation, depending on the facility and material. Many laboratories also hold NATA accreditation to ISO 15189, making traceability and corrective action operational requirements.

Build a risk-based specimen retesting policy

Begin by defining what counts as a retest: a new test performed because confidence in the original result has been reduced. State which materials and results are in scope, including primary clinical samples, retained aliquots, stained slides, culture isolates and electronic reports. Distinguish a repeat technical test from confirmatory testing already built into the routine TB diagnostic algorithm. Name the incident coordinator, bench supervisor, microbiologist and person authorised to release amended results.

Use a decision table rather than recollection after an event. For every affected test, record the failure mode, interruption duration, specimen type and processing stage, equipment condition, environmental records, quality-control status and whether the result is clinically critical. A minor paper-feed error may affect one report; a prolonged incubator excursion may affect many cultures. The GLI Phase 1 quality guidance can place equipment, safety and documentation controls within the broader phase-based quality system.

Pause work and protect specimens during the event

Pause work when safe operation cannot be assured. Place equipment in a documented safe state according to manufacturer instructions, and never ask staff to improvise electrical repairs. Record outage start and restoration times, generator status, monitored temperature and humidity, alarms, error codes, specimen locations and staff present. Preserve power logs and instrument audit trails before restarting or updating the LIMS.

Quarantine affected specimens, slides and isolates with labels showing deviation review. Do not discard, pool or decontaminate material merely to restore workflow. Maintain chain of custody and retain an aliquot for repeat testing when validated storage conditions permit. If a biological safety cabinet, autoclave, negative-pressure system or alarm has failed, suspend aerosol-generating work until the safety lead or engineer confirms controls are restored.

Review biosafety alongside analytical validity. A sample may remain uncontaminated yet lose analytical integrity, while an unsafe recovery attempt can create contamination. Use the practical laboratory safety checklist to support a rapid hazard assessment, PPE check, spill response, waste route and restart authorisation. This is particularly important in low-resource TB laboratories where specialist support may be remote.

Set clear triggers for holding and retesting

Define triggers before an event occurs. Appropriate triggers include failed instrument quality control after restart, an unresolved error code, an environmental excursion affecting specimens or reagents, an incomplete run, lost traceability, suspected sample mix-up, an invalid result, or any result whose integrity cannot be demonstrated. Tie each trigger to the affected batch and time window instead of applying it to every sample handled that day.

Also specify evidence that closes a trigger without retesting. A test completed before a protected backup failed, with continuous monitoring, passed controls and complete audit trails, may remain valid after documented review. A specimen incubated without a reliable temperature record, or run on an instrument that failed its post-outage check, should usually be repeated. Seek senior review for high-consequence results, including a positive TB molecular test.

Include a stop rule for inconclusive repeat testing. If valid methods disagree, keep the original result under review rather than silently replacing it. The authorised microbiologist should examine sample quality, contamination, reagent lots, instrument logs and operator records, then arrange referral or further testing under the approved algorithm. State when a report is corrected, when a supplementary report is issued and when the ordering clinician and relevant TB program are notified.

Choose defensible repeat testing methods

Prefer a retained aliquot tested by the original validated method when its storage history is documented and the reagents and instrument pass post-event quality control. This detects a potentially random analytical failure but may not reveal a method-specific problem. Testing a second aliquot with the same assay adds little when both share the same processing, storage or reagent history, so discourage blind duplication.

Where the original method’s validity is doubtful, use an independent principle validated for the sample type and intended purpose. This might involve an alternative nucleic-acid amplification target, extraction from the primary specimen, re-identification of a culture isolate, or referral to another accredited laboratory. Select the method according to biosafety, available volume, turnaround and the risk of exhausting diagnostic material. Approve any outage-recovery method through document verification and change control.

Prepare a controlled retest plan linking each original result to its repeat. Use unique identifiers, verify request and patient identifiers at the bench, and record operator, date, instrument, reagent lot and control status. Reconcile all repeats with the LIMS before authorisation. If results differ materially, retain both records, document the investigation, obtain authorised sign-off and communicate the clinically meaningful interpretation.

Manage deviations, reporting and corrective action

Open a deviation or non-conformance record for every significant event. Capture the malfunction or outage, containment, affected specimens and results, risk assessment, retest decision, actions, clinical notification, root cause and closure approval. Preserve relevant QC charts, temperature records, maintenance tickets, generator logs and instrument audit-trail screenshots. Link these records to the report so an assessor can reconstruct the decision months later.

Follow escalation routes without delaying urgent care. Notify the treating clinician, laboratory director and state or territory TB program when a result may affect isolation, treatment or contact management. If a malfunction may involve an IVD performance problem, assess whether a report to the TGA or manufacturer is required under current procedures, and record the decision even if no external report is made. Corrective action should fix the cause; preventive action should include maintenance, alarm testing, backup-power exercises, training and policy review.

Recommendations for a resilient Australian TB laboratory

A workable policy combines clear rules with practical support for staff applying them during a stressful event. These measures are especially useful where outages, courier delays and limited technical support coincide:

Embed the plan in induction, competency assessment and team drills. Involve scientists, quality managers, biosafety staff, engineers, couriers and clinical TB teams, including services delivering care to Aboriginal and Torres Strait Islander communities. Their feedback helps make escalation culturally safe, transport arrangements realistic and result communication prompt.

Activate the policy and sustain readiness

Approve the policy through the laboratory’s quality governance process, then pilot it during a simulated equipment failure. Require the team to identify affected work, pause testing, preserve samples, consult the decision table and authorise results. Include an overnight outage, a failed temperature alarm and manual record recovery in the scenario. Measure decision time and identify specimen or data gaps.

Keep the policy current. Review it after significant malfunctions, regulatory changes, new assays, supplier interruptions or quality-assurance findings, and at least on a scheduled annual cycle. Version every revision, withdraw obsolete forms and train staff. Internal audits and external quality assessment should test whether retesting decisions are consistent and whether reports remain traceable from the original specimen to final authorisation.

Use the GLI Quality Tool checklists to turn the procedure into everyday practice across the four improvement phases. Assign an owner for the SOP, incident form, retest log, backup-power procedure and annual review, and set a date for the next drill. A signed policy and completed drill provide a strong starting point for consistent, safe specimen recovery when a real malfunction or outage occurs.