Setting up smear microscopy proficiency testing in TB laboratories
A reliable proficiency testing program gives a tuberculosis laboratory an independent check that staff can detect acid-fast bacilli, apply the correct grading system and report results consistently. It tests the complete examination process rather than relying on a supervisor’s observation or an occasional review of stained slides.
Smear microscopy remains useful even as molecular assays become more common. It can support rapid assessment of infectiousness, help monitor treatment response and provide an accessible method where advanced platforms are limited. In Australia, it may also support services linked to remote communities, migrant and refugee health programs, hospitals and public health reference laboratories.
The program should be designed around the laboratory’s actual workload and risks. A small regional service may need a simple annual panel coordinated by a state or territory reference laboratory, while a larger network may run several rounds each year for multiple sites. The aim is a fair, documented assessment that improves practice rather than punishes individual staff.
A good starting point is the GLI Quality Tool’s quality management roadmap. Its guidance connects external assessment with personnel competency, equipment, documents, safety and continual improvement, allowing proficiency testing to become part of routine laboratory management rather than a separate exercise.
Define the purpose and scope
Begin by writing a short policy that explains what the program will assess. Scope may include specimen receipt, smear preparation, staining, microscopic examination, grading, result entry, authorisation and referral of unusual findings. If the laboratory also performs fluorescence microscopy, digital review or rapid molecular testing, keep those activities clearly separated unless they are assessed through an appropriate scheme.
The policy should identify participating staff, the test method, the number of rounds, acceptance criteria and responsibilities. Include bench scientists, rotating staff, trainees and relief personnel who may report TB smears. A program that assesses only the most experienced microscopist gives an incomplete picture of service capability.
Set realistic objectives. These could include detecting all positive smears, correctly classifying negative material, achieving agreement on bacillary grading and recognising poor staining or unsuitable slides. The program should also identify system failures, such as unclear result codes, transcription mistakes or delays in communicating a positive result.
Build governance and risk controls
Assign a program coordinator with authority to prepare or obtain panels, maintain participant codes, issue instructions, review results and document corrective actions. A second person should verify panel identity and results before distribution. Separating preparation from scoring reduces the risk of accidental disclosure or biased assessment.
Use a documented risk assessment before the first round. Consider infectious material, breakage during transport, loss of temperature control, incorrect participant identification, damaged slides and unauthorised access to results. Prepared, fixed slides are generally easier to transport and safer than unfixed material, but they still require suitable packaging, labelling and handling instructions.
Australian laboratories should align the scheme with their existing accreditation and governance arrangements, including NATA expectations where applicable and local state or territory procedures. A network serving Western Australia, the Northern Territory or far north Queensland may need extra time for freight and replacement shipments. Build those practical realities into the schedule rather than treating late delivery as participant failure.
Choose specimens and scoring rules
A useful panel contains a balanced mix of negative and positive smears. Positive material should represent relevant grading levels, including low-level positives that challenge the reader without creating an unfair guessing exercise. Include a high-grade positive where appropriate, as well as a negative slide with a clean background and acceptable staining quality.
Each slide needs a unique code, a reference result and a secure record of preparation, storage and verification. At least two competent readers should confirm the assigned result, with an adjudicator resolving disagreements. If digital images are used, confirm that image quality, magnification and viewing conditions are comparable for all participants.
Use a recognised grading framework and publish it before assessment begins. The scoring system should give greater weight to clinically important errors, such as reporting a positive slide as negative. A minor grading variation on a low-positive smear may require coaching and monitoring rather than automatic failure, provided the laboratory’s policy defines that response in advance.
Set up distribution and reporting
Send each participant clear instructions covering the deadline, microscope requirements, staining expectations if slides require further processing, result terminology and escalation arrangements. Participants should work under normal conditions and should not receive hints about the panel composition. Code results so the coordinator can analyse performance while limiting unnecessary disclosure of individual staff identities.
Record dispatch and receipt dates, slide condition, reader identity, method used and result submission time. For services in the bush or across island and remote communities, use a distribution window that allows for courier delays and public holidays. A state reference laboratory can help coordinate shipments so that a remote site is assessed under the same conditions as a metropolitan service.
Issue a report promptly after the closing date. It should show the participant’s results against the assigned results, item-level agreement, grading differences, errors, comments and the required follow-up. Avoid publishing names in group reports. A network-wide summary can show common weaknesses without turning the exercise into a public ranking.
Use results to confirm competence
Review each discordant result promptly, especially a false-negative result. Examine the original slide, staining quality, microscope condition, workload, lighting, reader fatigue and reporting workflow. A discrepancy may reflect a technical problem rather than a knowledge gap, so the investigation should cover the full testing pathway.
Corrective action might include a supervised repeat, review of the staining method, microscope maintenance, refresher training, a second-read requirement or temporary restriction of independent reporting. Actions should have an owner and due date. The coordinator should later verify whether the action worked through direct observation, internal quality control or a subsequent assessment round.
Use results to identify trends across the service. Repeated weak performance by several sites may indicate an unsuitable stain, inconsistent reagents, poor slide quality or unclear instructions. Repeated errors by one reader may require a structured competency assessment. Treat proficiency testing as evidence for improvement, not as a substitute for daily internal quality control.
Fit the program to Australian services
Australia’s low incidence of tuberculosis can make it difficult for some laboratories to maintain frequent exposure to positive smears. A centralised panel system can provide regular practice without requiring every hospital or regional laboratory to retain a large collection of positive material. Reference services in Sydney, Melbourne, Brisbane, Perth, Adelaide, Darwin and other centres can support smaller sites through agreed referral and assessment arrangements.
The program should also account for culturally safe and equitable service delivery. Laboratories supporting Aboriginal and Torres Strait Islander communities may work across substantial distances and with referral pathways that involve community-controlled health services. Clear communication, reliable transport and respectful handling of patient-linked information matter as much as the technical panel design.
Migrant and refugee health services may encounter different patient populations and referral patterns from those seen in a rural hospital. Staff should understand when a smear result requires urgent communication, confirm the local notification pathway and know when to refer specimens for culture or molecular confirmation. Proficiency testing should reinforce these interfaces without assigning tasks outside the laboratory’s authorised scope.
Connect assessment with the quality system
Keep the program inside the laboratory’s document control system. Store the policy, panel inventory, assigned results, distribution log, participant submissions, reports, investigations and corrective action records in a controlled location. The GLI resource provides practical phase-specific checklists that can help a laboratory connect this work with equipment, personnel, documents, assessment and continual improvement requirements.
Review the program after every round and formally at least once a year. Check whether the panel was difficult enough, whether the turnaround time was practical, whether the scoring rules produced useful decisions and whether participants received feedback promptly. Update the program when the laboratory changes stains, microscopes, reporting software, staffing or referral arrangements.
The distinctions below help prevent overlapping activities from being treated as interchangeable.
| Activity | Main purpose | Typical material or evidence | Frequency | Response to a problem |
|---|---|---|---|---|
| Internal quality control | Check daily testing conditions | Control slides, stain checks, microscope checks | Each run or scheduled work period | Fix the immediate technical issue and document it |
| Proficiency testing | Compare performance with assigned results | Coded positive and negative slides or approved images | Several times a year or according to risk | Investigate errors, provide corrective action and reassess |
| Competency assessment | Confirm an individual can perform the whole task | Observation, unknown samples, questions and record review | At induction and periodically | Retrain, supervise and repeat assessment |
| Internal audit | Check whether the system follows its procedures | Records, interviews, observations and traceability checks | Planned audit cycle | Correct process or documentation gaps |
| External accreditation assessment | Evaluate the quality system against requirements | Documents, interviews, records and observed practice | According to accreditation cycle | Address findings through a formal improvement plan |
Start with a manageable pilot involving the staff and sites that perform the most smear microscopy. Document the workflow, run a small panel, review the findings and adjust the logistics before expanding across the network. With clear governance, fair scoring and timely follow-up, the program can strengthen diagnostic confidence from a metropolitan reference laboratory to a remote service.
Make the first round part of the laboratory calendar, assign its coordinator, approve the policy and secure suitable coded slides. Review each result as a learning opportunity, close corrective actions with evidence and use the next round to demonstrate measurable improvement in TB smear microscopy.