How to Conduct an Internal Audit of Your TB Laboratory’s Quality System
An internal audit gives a tuberculosis laboratory a structured way to determine whether its quality management system is working as intended. It examines documented procedures, daily practices, technical performance, staff competence, records, and improvement activities. The goal is not to assign blame. It is to identify risks before they affect results, patients, staff, or public health decisions.
A well-planned audit compares actual laboratory operations with approved procedures, regulatory requirements, accreditation standards, and the laboratory’s own quality objectives. It should cover the complete testing pathway, from specimen collection and transport through testing, reporting, result review, and corrective action.
The GLI Quality Tool provides a practical framework for laboratories working in different resource settings. Its four-phase roadmap is organized around twelve Quality Systems Essentials, helping an audit team assess both technical functions and the management processes that support reliable TB diagnosis.
Define The Audit Scope And Objectives
Begin by stating what the audit will examine and why. A laboratory may audit its entire quality system annually, or focus on a specific risk such as specimen rejection, equipment maintenance, biosafety, result reporting, or staff competency. A clearly defined scope prevents the audit from becoming an unfocused review of every available document.
Set objectives that can be assessed with evidence. For example, an objective might be to determine whether all staff performing molecular testing have current competency records, whether control results are reviewed before patient results are released, or whether corrective actions are completed within agreed timeframes. Include the departments, testing platforms, shifts, locations, and records covered by the audit.
Select criteria before collecting evidence. These may include standard operating procedures, national TB guidance, manufacturer instructions, internal policies, accreditation requirements, and the twelve Quality Systems Essentials. Establishing criteria in advance makes findings more consistent and helps staff understand how conclusions were reached.
Prepare The Audit Team And Evidence
Assign an audit lead who understands laboratory quality management and can remain impartial. Auditors should not assess work for which they have direct responsibility whenever possible. Include personnel with relevant technical, biosafety, quality, and supervisory knowledge, while keeping the team small enough to work efficiently.
Prepare an audit schedule that identifies activities, responsible auditors, locations, and expected participants. Review previous audit reports, nonconformity logs, proficiency testing results, incident reports, customer complaints, quality indicators, and management review records. These sources can highlight areas requiring closer attention.
Before the audit begins, review the user instructions for the GLI Quality Tool so that phase-specific checklists and guidance are applied consistently. Adapt the checklist to the laboratory’s testing methods and operating context, but do not remove questions simply because a process appears routine.
Prepare evidence-gathering tools, including interview prompts, observation sheets, document review forms, and a method for classifying findings. Auditors should record objective evidence rather than impressions. Useful notes identify what was reviewed, where it was found, who was involved, and how the evidence relates to the audit criterion.
Review The Quality System Systematically
Conduct the audit by following the laboratory’s actual workflow. Start with management responsibility and quality objectives, then review personnel, organization, training, purchasing, equipment, documents, information management, process control, assessment, and continual improvement. The twelve Quality Systems Essentials provide a useful structure for ensuring that important management functions are not overlooked.
Use three complementary methods: document review, interviews, and direct observation. A procedure may be current and approved, while staff practice differs from it. Conversely, staff may follow a reliable process that has not been documented. Comparing these sources reveals gaps between intended, recorded, and actual practice.
Trace selected specimens or results through the complete testing process. For example, choose a recent specimen and verify its receipt, identification, acceptance decision, preparation, test run, quality control, result authorization, reporting, and record retention. This “vertical audit” can reveal connections between several quality elements that a document-by-document review might miss.
| Audit area | Evidence to review | Questions to verify |
|---|---|---|
| Personnel and competency | Job descriptions, training files, competency assessments | Are staff authorized and periodically assessed for assigned tasks? |
| Equipment and supplies | Inventory, maintenance logs, temperature records, stock cards | Are equipment and critical materials available, maintained, and monitored? |
| Documents and records | Controlled procedures, revision history, completed worksheets | Are current instructions accessible and records complete and legible? |
| Testing process | Run logs, quality control results, rejected specimens | Are testing steps, controls, and acceptance decisions performed consistently? |
| Assessment | Proficiency testing, internal quality control trends, audit reports | Are performance results reviewed and acted upon? |
| Improvement | Nonconformity reports, root-cause reviews, action plans | Are corrective actions effective and closed with evidence? |
Observe Work And Interview Personnel
Observation should focus on what happens during routine work, not a staged demonstration. Watch specimen handling, use of personal protective equipment, workflow separation, equipment operation, contamination control, data entry, result authorization, and waste management. Record both compliant practices and deviations from approved procedures.
Interviews help auditors understand why a process operates as it does. Ask open, neutral questions such as how staff know which procedure is current, what they do when quality control fails, where they report equipment problems, and how they respond to a mislabeled specimen. Answers should be checked against records and observation rather than accepted as proof by themselves.
Include staff from different roles and shifts when practical. A process may be well controlled during normal working hours but less reliable during weekends, night shifts, staff shortages, or instrument downtime. Consider whether temporary personnel, referral sites, couriers, clinicians, and information officers understand the parts of the testing pathway that affect laboratory quality.
Maintain a respectful tone throughout the audit. Staff are more likely to disclose workarounds, resource constraints, and recurring problems when the audit is presented as a mechanism for strengthening patient services. Confidentiality, professional conduct, and clear explanations are essential for obtaining trustworthy evidence.
Classify Findings And Assess Risk
Write each finding in a way that connects the requirement, evidence, and risk. A strong finding states what should happen, what was observed, and why the difference matters. For example, instead of writing “maintenance is poor,” specify that a maintenance record for a critical instrument lacked the required monthly verification for three consecutive months, creating uncertainty about instrument performance.
Separate nonconformities from observations and opportunities for improvement. A major nonconformity may involve a failure that could compromise patient results, biosafety, regulatory compliance, or the integrity of the quality system. A minor nonconformity may be isolated or limited in effect. An observation identifies a potential weakness that has not yet produced a confirmed failure.
Use a consistent risk assessment method. Consider the likelihood of occurrence, potential impact, detectability, and the number of specimens or results affected. High-risk findings should receive prompt containment, while lower-risk issues can be managed through planned improvement. If an immediate threat exists, notify the laboratory manager during the audit rather than waiting for the final report.
Hold a closing meeting to explain the evidence, confirm factual accuracy, and discuss preliminary priorities. The closing meeting should not become a negotiation over whether an uncomfortable finding is recorded. However, staff should have an opportunity to clarify misunderstandings, provide missing records, and identify practical constraints that affect corrective action.
Report Results And Track Corrective Action
The audit report should include the scope, criteria, dates, auditors, areas reviewed, strengths, findings, risk ratings, and required actions. Link each finding to objective evidence and identify the responsible person or function. Avoid vague recommendations such as “improve documentation”; state what record, procedure, training activity, or control must be established or corrected.
A corrective action plan should address the underlying cause rather than only the visible symptom. Root-cause analysis may reveal insufficient training, unclear responsibilities, poor document control, inadequate supplies, equipment limitations, or a process designed without enough safeguards. Actions should include deadlines, required resources, and a method for verifying completion.
Use the following practices to make follow-up effective:
- Contain any immediate risk before investigating the wider cause.
- Assign one accountable owner for every corrective action.
- Set realistic deadlines based on patient and biosafety risk.
- Verify implementation through records, observation, interviews, or repeat testing.
- Confirm effectiveness after enough time has passed to show sustained improvement.
Track actions in a central log and review progress during quality meetings or management review. Closure should require evidence that the action was implemented and that it reduced the original risk. Repeated findings should trigger escalation, a broader root-cause review, or a change in the laboratory quality objective.
Use Audits To Strengthen Continual Improvement
An internal audit is most valuable when its results influence everyday management decisions. Combine audit findings with quality indicators such as turnaround time, invalid test rates, specimen rejection, contamination, equipment downtime, proficiency testing performance, and amended reports. Trends can show whether a recurring issue is local or reflects a system-wide weakness.
Share relevant lessons with staff without exposing individuals unnecessarily. Short feedback sessions, revised work instructions, targeted competency assessments, and visual reminders can help translate findings into safer practice. Where a finding is linked to resource limitations, document the risk and use evidence from the audit to support procurement, staffing, infrastructure, or training requests.
The GLI Quality Tool’s downloadable materials can support preparation, assessment, and follow-up as the laboratory develops its quality management system. Use the resources alongside national requirements and local procedures, tailoring the audit depth to the laboratory’s phase of development and testing services.
Schedule the next review according to risk, previous performance, and the importance of the process. A laboratory with repeated high-risk findings may need a focused reassessment within weeks or months, while a stable process may be reviewed during the next planned audit cycle. Document the decision so the audit program remains deliberate rather than calendar-driven.
Start with one defined process, gather evidence from documents, people, and observation, and record findings precisely. Then assign corrective actions, verify their effectiveness, and share the lessons with the wider laboratory team. A disciplined internal audit turns the quality system from a set of documents into a working instrument for dependable TB diagnosis and continuous public health protection.