Laboratory Audits: Definition, Types, Requirements, and Process

An audit is a documented process that obtains evidence and objectively evaluates whether specific criteria are met. A laboratory audit evaluates laboratory operations, documentation, and quality systems to verify regulatory compliance and ensure data integrity. Laboratory audits include internal audits and external audits.

Laboratories are subject to various audit requirements depending on applicable standards and regulations such as ISO/IEC 17025 and ISO 15189, Good Laboratory Practice (GLP), Good Manufacturing Practice (GMP), Clinical Laboratory Improvement Amendments (CLIA), and others.

A typical laboratory audit involves defining the audit scope, selecting auditors, planning the audit, reviewing documents and records, observing laboratory processes, identifying and recording findings, issuing a report, and performing corrective actions and preventive actions (CAPA) follow-up for closure of findings.

Laboratory audit readiness requires organizations to maintain an up-to-date quality management system, adhere to internal procedures, conduct internal audits, train staff, track corrective actions, and organize documentation accessibly.

An electronic Quality Management System (eQMS) with an integrated audit module increases audit efficiency and ensures traceability.

SimplerQMS is fully validated eQMS software designed for life science companies, including laboratories. SimplerQMS offers comprehensive audit management capabilities that support compliance with ISO, GMP, GLP, and CLIA requirements. In addition to audit management, SimplerQMS includes modules for document control, training, CAPA and equipment management, and more — all integrated to support total quality management.

What is a Laboratory Audit?

A laboratory audit is a systematic, documented evaluation of laboratory operations and quality systems to determine compliance with defined standards, regulatory requirements, or internal policies. Laboratory audits assess methods, processes, equipment, personnel competency, and documentation to ensure the reliability, traceability, and integrity of laboratory results.

The purpose of laboratory audits is to verify compliance, ensure the accuracy of data, improve processes, and often maintain accreditation or certification. Audits identify areas for improvement and ensure that laboratories consistently produce valid and reliable results.

Laboratory audit execution involves diverse auditors such as internal teams, independent contractors, regulatory bodies, accreditation organizations, and customers. Laboratory audits typically arise in response to certification cycles, critical quality incidents, or regulatory compliance mandates.

Internal audit activities under Good Manufacturing Practice (GMP) and ISO (International Organization for Standardization) frameworks are required to occur periodically, but a specific interval is not mandated. An annual audit cycle is commonly implemented in laboratories to verify compliance and effectiveness of the quality management system.

External audit timelines follow more defined cycles, with ISO recertification audits occurring usually triennially, surveillance audits annually, and Good Laboratory Practice (GLP) inspections in Europe generally every two or three years.

Why Laboratory Audits are Important?

Laboratory audits are important because they verify compliance with regulatory requirements, ensure data integrity, and confirm that test results produced by the specific laboratory are reliable.

The main benefits of laboratory audits are listed below.

• Promoted Accountability: Laboratory audits enforce responsibility for adhering to standard procedures and quality benchmarks across staff and systems.
• Improved Quality Control: Audits identify procedural gaps, documentation errors, or non-conformities that could affect test reliability.
• Ensured Adherence to Regulatory Standards: Audits verify that a laboratory consistently meets requirements for standards and guidelines, such as ISO/IEC 17025, GLP, and GMP.
• Prevented Errors: Audits prevent errors through systematic evaluation of instrument calibration, personnel training, and method validation. Regular reviews of processes and records uncover inconsistencies early, reducing the risk of data manipulation or accidental mistakes.
• Safeguarded Data Integrity: Laboratory audits confirm the traceability, completeness, and authenticity of laboratory records, securing scientific and regulatory trust.
• Fostered Continuous Improvement: Audits highlight process deficiencies and trigger corrective actions that lead to stronger quality systems.
• Supported Accreditation, Client Trust, and Legal Compliance: Audits provide verifiable evidence of operational control, readiness for inspection, and fulfillment of contract and regulatory obligations.

What Are the Common Formats Used in Laboratory Audits?

The common formats used in laboratory audits are on-site audits and remote audits. Each audit format is selected based on risk, audit scope, accessibility, and regulatory requirements. Some audits may use a hybrid model, starting remotely and concluding on-site.

On-site audits involve auditors visiting the laboratory to perform a tour of facilities, observe procedures, examine equipment, interview staff, and inspect records in person. On-site audits are typically performed for initial certifications, regulatory inspections, supplier qualifications, or when physical verification is essential.

Remote audits are conducted through digital means such as video conferencing, screen sharing, and document portals. Auditors assess compliance by reviewing electronic records, interviewing staff online, and observing procedures via live video. Remote audits are often used for surveillance audits, follow-ups, or during travel restrictions.

What are the Different Types of Laboratory Audits?

The types of laboratory audits fall into two broad categories – internal audits and external audits. These classifications define who conducts the audit and the specific objectives behind it.

• Internal Audits: Internal audits, required by standards such as ISO 9001 and ISO/IEC 17025, ensure that organizations adhere to defined internal procedures and standard criteria. These audits are typically conducted by personnel who are independent of the area being audited (eg quality assurance) or by external auditors to monitor compliance and evaluate performance gaps. In a related context, the EU-GMP guidelines, under Chapter 9 of EudraLex Volume 4, mandate self-inspections to verify regulatory alignment. Supplementing these formal procedures, mock audits function as proactive simulations designed to uncover process deficiencies and bolster staff preparedness for upcoming regulatory or certification inspections.
• External Audits: External audits in laboratories assess compliance with regulatory, contractual, or quality requirements, involving inspections by authorities such as the FDA, EMA, or national authorities to ensure adherence to GLP or GMP guidelines. Certification audits verify alignment with international quality standards like ISO/IEC 17025 or ISO 15189, while surveillance audits ensure continued compliance between certification cycles. For-cause audits are triggered following significant quality incidents such as critical deviations, non-conformities, or complaints. Supplier audits evaluate laboratories as part of customer’s internal qualification process for their suppliers.

Internal Audits

Internal audits are systematic evaluations conducted by the personnel who are independent of the area being audited or qualified external contractors to verify compliance with internal procedures, and applicable requirements. Internal audits are also verifying that the laboratory’s quality management system is effectively implemented and maintained.

The objective of internal audits is to detect non-conformities, ensure adherence to standard operating procedures, and drive continuous improvement. Internal audits are a key requirement under international standards, such as ISO 9001 and ISO/IEC 17025, and guidelines like GMP.

The categories of internal audits are listed below.

• Routine Internal Audits: Routine internal audits evaluate compliance with the laboratory’s Quality Management System (QMS) and applicable ISO standards, such as ISO 9001:2015 and ISO/IEC 17025:2017. Laboratory internal audits are mandated under ISO/IEC 17025 and must be carried out at defined intervals. Although ISO does not specify the frequency, it is common practice to perform annual internal audits. Internal audits are executed by a trained and impartial laboratory employee or internal audit team to ensure objectivity and consistency in laboratory audit practices.
• Self-Inspections: Self-inspections serve as GMP-specific laboratory audits aligned with Eudralex Volume 4, focusing on the internal review of GMP compliance. Self-inspections examine elements such as laboratory personnel training records, facility conditions, laboratory equipment calibration, controlled documentation, data integrity, and analytical testing workflows. Self-inspections are conducted at laboratory-defined frequencies based on the quality system and are performed by qualified personnel independent of the inspected area. Observations and deviations are documented, with corrective actions linked directly to findings.
• Mock Audits: Mock audits are preparatory laboratory audits, replicating the conditions of actual inspections from regulatory authorities or certification bodies. Mock audits are typically facilitated by third-party auditors or consultants to identify compliance gaps, enhance audit preparedness, and train laboratory staff under realistic conditions. Although there is no fixed schedule, mock laboratory audits are usually timed ahead of key milestones such as certification renewals or initial regulatory inspections to ensure readiness and corrective planning.

External Audits

External audits are formal assessments conducted by parties outside the laboratory to evaluate compliance with regulatory, contractual, or accreditation requirements. The objective of external audits is to independently verify that the laboratory meets applicable requirements, produces valid results, and maintains data integrity and an efficient quality management system.

The categories of external laboratory audits are listed below.

• Regulatory Audits: Regulatory audits assess laboratory compliance with applicable legislation through external inspections by agencies such as the FDA (21 CFR Part 211 for GMP, 21 CFR Part 58 for GLP), EMA, and EU national authorities under Eudralex Volume 4. Regulatory audits evaluate quality management systems and legislative adherence. Audits by the Centers for Medicare & Medicaid Services (CMS) ensure compliance with CLIA under 42 CFR Part 493 for clinical laboratory testing. Inspections of laboratories involved in clinical trials focus on ensuring compliance with GCP standards. Regulatory audits are typically risk-based, occurring on a scheduled cycle (eg every two to three years), but may be triggered more frequently due to submissions or critical quality issues.
• Certification Audits: Certification audits are external laboratory assessments performed by accreditation bodies to ensure compliance with standards like ISO/IEC 17025:2017, ISO 15189:2022, and ISO 17043:2023. Certification audits follow a structured accreditation cycle starting with an initial audit and followed by periodic re-certification audits (typically every 3 years) to verify continued conformity.
• Supplier Audits: Supplier audits are conducted to qualify laboratories providing testing or analytical services. Supplier audits evaluate a lab’s ability to meet contractual quality requirements and include reviews of QMS compliance, testing procedures, equipment calibration management, and validation documentation, among others. Supplier audits are performed by clients or third-party auditors. Supplier audits are scheduled between the laboratory and the client and usually follow a defined audit frequency schedule (typically ranging from 1 to 3 years, depending on supplier risk and performance).
• For-Cause Audits: For-cause audits are unscheduled external assessments triggered by complaints, out-of-specification (OOS) results, deviations, or non-conformities. For-cause audits focus on root cause investigation, risk management, and CAPA implementation. Conducted usually by regulators or clients, for-cause audits ensure the lab’s quality investigation and CAPA processes are adequate and that the lab’s operations align with expected regulatory requirements.
• Surveillance Audits: Surveillance audits are scheduled reviews by accreditation bodies between full certification cycles. Surveillance audits monitor continued compliance with accreditation standards such as ISO/IEC 17025 or ISO 15189. Typically, surveillance audits are performed annually or biennially and ensure that the laboratory remains in conformity throughout the certification period.

What are the Audit Requirements for Laboratories?

Audit requirements are derived from standards, regulations, and guidelines that laboratories must follow to demonstrate competence, data integrity, and regulatory compliance to ensure the reliability of produced results.

The main requirements applicable to laboratory audits are listed below.

• Eudralex Volume 4, Chapter 6: Applies to cGMP-compliant quality control laboratories in the EU or operating under EU-GMP guidelines. Chapter 6 requires, among others, documented testing, sampling, and recording procedures, as well as procedures and records for instrument calibration, data traceability, validation, or verification of analytical methods. Laboratories must ensure that results are consistent with specifications and that there is an established procedure for the investigation of out-of-specification (OOS) and out-of-trend (OOT) results.
• 21 CFR Part 211: Enforced by the FDA for GMP compliance in quality control labs. 21 CFR Part 211 mandates accurate recording, established specifications, standards, sampling plans, written test procedures, calibration performance at suitable intervals, and documented reviews. FDA requires quality control labs to retain complete data from all tests and follow written procedures strictly.
• GLP (OECD Principles of GLP): Applies to laboratories performing non-clinical safety studies in the EU, ensuring GLP compliance including data reliability, integrity, and traceability.
• 21 CFR Part 58: Governs non-clinical laboratory studies under the GLP framework. 21 CFR Part 58 includes requirements for study protocols, standard operating procedures (SOPs), equipment maintenance and calibration, quality assurance units, and data archives. All activities must ensure traceable, verifiable, and accurate test results.
• ISO/IEC 17025: Defines general requirements for the competence of testing and calibration laboratories. Labs must implement a quality management system, maintain documented procedures, select, verify, or validate their methods, ensure personnel competency, and establish an equipment calibration program.
• 42 CFR Part 493 (CLIA): U.S. regulations for clinical laboratories performing human diagnostic testing. Requirements include proficiency testing, personnel qualifications, and quality systems, including quality control and record retention.
• ISO 15189: Sets quality and competence standards for medical laboratories performing clinical testing on human specimens. The format of ISO 15189:2022 is based on ISO/IEC 17025:2017. ISO 15189:2022 covers quality management, pre-examination, examination, and post-examination processes, personnel competence, and risk management. ISO 15189 emphasizes continual improvement and customer communication.
• CLSI (Clinical and Laboratory Standards Institute): CLSI provides consensus-based clinical lab standards. CLSI requirements provide a comprehensive framework for laboratory quality management through their 12 Quality System Essentials. 
• GCLP (Good Clinical Laboratory Practice): GCLP guidelines combine principles from GLP and GCP for labs supporting clinical trials, covering elements such as specimen handling, equipment calibration, data management, and quality assurance and reporting to ensure trial data integrity.
• ISO 17043:2023: Specifies requirements for proficiency testing providers. Proficiency testing is an essential tool for demonstrating the competence of conformity assessment bodies. Proficiency Testing involves the use of interlaboratory comparisons for the evaluation of laboratory performance. ISO 17043 includes confidentiality, impartiality, technical competence, design and operation of proficiency testing schemes, and evaluation of participant performance.

Auditors focus on key areas such as testing processes, SOP adherence, equipment calibration and maintenance, staff training and qualifications, traceability of results, and the overall effectiveness of the quality management system. Review of raw data and audit trails, OOS/OOT handling, and records related to method validation or method transfer are also common during an audit.

Audit requirements differ based on audit type (internal or external), laboratory category (clinical, non-clinical, research, or environmental), and regulatory jurisdiction. Laboratories must align their systems with the specific frameworks and regulatory standards applicable to their operations.

How to Conduct a Laboratory Audit?

To conduct a laboratory audit, an organization must follow a structured process to evaluate compliance with defined requirements, identify nonconformities, and ensure the integrity of laboratory operations.

The ten stages of a laboratory audit performance are listed below.

1. Define the Audit Scope and Objectives: Define the audit scope and objectives, such as regulatory inspection, internal quality audit, or third-party supplier evaluation. Within the audit scope, identify the departments, systems, and compliance requirements involved. Reference applicable compliance standards or regulatory frameworks directly in the scope, such as ISO/IEC 17025 for general requirements for the competence of testing and calibration laboratories, or GMP for quality control laboratories testing medicinal products.
2. Select and Train Auditors: Select independent auditors trained in audit techniques, findings classification, regulatory requirements, and quality standards. The lead auditor should have been engaged in sufficient inspections in the roles of observer and co-auditor to ensure experiential competence.
3. Develop an Audit Plan: Develop a comprehensive audit plan that includes objectives, timelines, audit criteria, team responsibilities, scope, and documents to be reviewed. Share the plan with stakeholders and include follow-up on any previously identified nonconformities or CAPAs when applicable.
4. Conduct the Opening Meeting: Initiate the audit process by presenting the audit plan and introducing the auditors. Ensure alignment on document access and clarify any confidentiality clauses.
5. Perform Document and Record Review: Review key documentation such as SOPs, validation records, test reports, equipment logs, and training records. Check documentation for accuracy, completeness, and alignment with applicable laboratory procedures and regulations.
6. Observe Processes and Interview Staff: Perform on-site observations of lab workflows to ensure procedural compliance. Conduct competency interviews to assess staff adherence to laboratory procedures and their understanding of quality practices.
7. Identify and Record Findings: Document findings and capture supporting audit evidence. Classify the findings and refer to applicable clauses from the requirement or standard violated for each finding (e.g. Clause 6.15 of EudraLex Volume 4, chapter 6).
8. Conduct the Closing Meeting: Summarize audit findings, their classifications, and associated risks. Confirm understanding with auditees, and present preliminary recommendations for corrective action suggestions. Discuss timelines and responsibilities for response.
9. Issue the Audit Report: Prepare and distribute a detailed audit report including the scope, methodology, findings, supporting documents, and required corrective actions. Include assigned responsibilities and due dates.
10. Follow-Up and Verify Corrective Actions: Verify the implementation and effectiveness of corrective actions by following up with CAPA closure. A re-audit or spot-check may be necessary, in case of major observations.

What Are the Advantages and Challenges Associated with Laboratory Audits?

Laboratory audits offer structured assessments that help laboratories maintain compliance, improve quality, and ensure reliable data. However, audits may also introduce certain operational burdens and risks if not managed properly.

The advantages of laboratory audits are listed below.

• Ensure Regulatory Compliance: Laboratory audits ensure regulatory compliance through confirmation of alignment with requirements such as ISO/IEC 17025, GMP, or GLP, reducing exposure to non-conformances and legal penalties.
• Improve Data Integrity: Laboratory audits improve data integrity through structured documentation reviews and traceability gap assessments that strengthen data accuracy and reproducibility.
• Enhance Quality Control: Laboratory audits enhance quality control through the evaluation of adherence to SOPs and validated testing methods, ensuring the reliability of analytical outcomes.
• Promote Accountability: Audits promote accountability by clarifying responsibilities across teams and reinforcing transparent operational practices.
• Support Continuous Improvement: Audits support continuous improvement with compliance gaps identification and CAPA initiation, driving measurable performance optimization.
• Facilitate Certification and Customer Trust: Laboratory audits facilitate certification and customer trust by showcasing technical proficiency, audit readiness, and regulatory alignment to clients, regulators, and accreditation bodies.

The challenges associated with laboratory audits are listed below.

• Resource Intensiveness: Laboratory audits require a significant allocation of personnel, time, and documentation efforts. During unannounced or extensive audits, resource allocation can lead to serious operational disruption.
• Stress on Staff: Audit activities, particularly unannounced audits or those with unclear communication, can cause audit fatigue and increased stress, potentially affecting overall lab performance.
• Risk of Negative Findings: Detection of non-conformities during a laboratory audit may necessitate corrective actions, threaten accreditation status (e.g., under ISO/IEC 17025 audits), and harm the lab’s reputation or client trust, especially if findings are publicly reported (e.g. FDA warning letters). In contrast, addressing these issues proactively through internal quality processes would allow for measured, strategic improvements and maintain customer trust.
• Cost Implication: External audits and their associated follow-up procedures may incur substantial costs. The cost of non-compliance, especially for facility or equipment-related findings, can be particularly burdensome for small or mid-sized labs with limited budgets.
• Over-Reliance on Checklist Approach: Focusing audits narrowly through a checklist-based methodology risks overlooking deeper systemic or procedural flaws. Over-reliance on checklists limits the effectiveness of audits in promoting continuous improvement and enhancing laboratory quality systems.

How to Ensure Laboratory Audit Readiness?

To ensure laboratory audit readiness, laboratories must engage in proactive laboratory audit preparation that aligns with quality standards and regulatory expectations.

The following seven steps support laboratories in maintaining a state of audit readiness.

1. Maintain an Up-to-Date Laboratory Quality Management System: Laboratory audit readiness begins with a current, documented QMS, covering testing procedures, equipment calibration processes, deviation or non-conformance reporting, and training matrices. A strong QMS foundation supports strong data integrity and laboratory compliance.
2. Follow SOPs and Internal Procedures Consistently: To ensure laboratory audit success, all staff must adhere to approved SOPs and promptly report any deviation or non-conformance. Procedure adherence supports regulatory inspection readiness and overall quality assurance.
3. Implement an eQMS with Audit Management Capabilities: Enhance laboratory audit readiness by using an electronic QMS that supports audit checklists, CAPA workflows, and audit trails. The system should allow real-time access to past and upcoming audit schedules, findings, and corrective actions.
4. Keep Documentation Complete and Accessible: Audit readiness requires that all test records, calibration certificates, validation reports, and training matrices be accurate, organized, and easily retrievable. A well-maintained document control system supports transparency and traceability during inspections.
5. Conduct Regular Internal Audits and Self-Inspections: Internal audits help identify gaps proactively and prepare the laboratory to face external audits by maintaining continuous audit readiness and alignment with applicable requirements.
6. Train Staff on Roles and Audit Expectations: Prepare laboratory personnel with role-specific training matrices and targeted audit interview prep. Staff must confidently articulate their responsibilities and demonstrate knowledge of the QMS during audits and inspections.
7. Establish Corrective Action Tracking: Track all nonconformities, deviations, complaints, and past audit findings through a structured CAPA system. Confirm closure and evaluate effectiveness to ensure regulatory compliance and reinforce ongoing laboratory audit readiness.

How Can Audit Management Software Streamline Laboratory Audit Processes?

Audit management software can streamline laboratory audit processes by automating workflows for planning, execution, documentation, and follow-up activities within a centralized digital environment. Audit management software ensures consistency, traceability, and efficiency in handling internal and external audits. An audit management solution, often part of a broader eQMS, helps laboratories schedule audits, document findings, assign corrective actions, and track CAPA closure in a structured and compliant way.

SimplerQMS provides a fully validated eQMS solution for laboratories and life science companies. SimplerQMS includes an audit management module that enables laboratories to manage audit programs more effectively while staying compliant with industry regulations.

In addition to audit management, SimplerQMS offers broad eQMS process support through modules for document control, training management, change control, CAPA management, equipment management, supplier management, risk management, complaint handling, and more.

SimplerQMS helps laboratories meet regulatory and certification requirements by supporting compliance with 21 CFR Part 211, Eudralex Volume 4, ISO 9001, and others. The document control module supports documentation handling processes with audit-ready version control and traceability. Training management guarantees that laboratory personnel are trained and qualified per ISO 15189 and CLIA requirements. CAPA management enforces traceable and systematic corrective actions in response to audit findings, satisfying GLP and ISO/IEC 17025 expectations.

How Do Laboratory Audits Differ from Pharmaceutical Audits?

The main difference between laboratory audits and pharmaceutical audits lies in their scope, regulatory focus, and industry context. Both aim to ensure compliance and quality, but they address distinct operational and regulatory priorities.

Laboratory audits focus on compliance with the approved testing methods and data integrity. Laboratory audits assess whether testing processes, calibration records, SOPs, and analytical methods meet standards such as ISO/IEC 17025, ISO 15189, or GLP (21 CFR Part 58). Audits verify that laboratory results are traceable, valid, precise, and scientifically sound.

Pharmaceutical audits focus on verifying product quality and safety, GMP compliance, and supply chain integrity by enforcing guidelines such as 21 CFR Part 211 and Eudralex Volume 4. Pharmaceutical audits assess manufacturing and distribution practices, batch records, and supplier evaluation to ensure consistent quality and traceability.

Laboratory audits can be GMP-based, but concentrate on testing accuracy, data integrity, and proper handling of laboratory records. While both audit types share compliance objectives, their focus differs based on whether the core activity involves manufacturing or laboratory testing.