QAC — Quality Accreditation Commission QAC Quality Accreditation Commission
Professional setting for technical guidance and advisories

Technical resources

Technical guidance and advisories

Technical guidance for conformity assessment bodies on interpreting accreditation requirements, maintaining competence, and demonstrating consistent, evidence-based practice.

Technical guidance for conformity assessment bodies

Interpreting requirements for consistent practice

Review international advisories, program-specific assessment guidance and technical resources to prepare for accreditation and demonstrate continuing competence, impartiality and reliable results.

01 / Standards & accreditation practice

Guidance on international advisories

Guidance addressing standards transitions, scope definition, and accurate representation of accredited activities, informed by relevant IAF and ILAC publications.

Guidance on standards transitions

Transition to New Standards

Coordinate changes to applicable standards through a documented transition plan that maintains competence and continuity of accredited activities.

  • Verify the applicable edition and scheme-specific transition deadline with QAC; implementation periods vary.
  • Examine revised requirements, identify gaps, and update procedures, personnel training, and assessment evidence.

Guidance on scope definition

Rules for Scope of Accreditation

Describe the scope of accreditation with sufficient clarity and precision to identify the activities for which competence has been demonstrated.

  • Identify relevant services, methods, standards, locations, and any limitations.
  • Maintain scope statements consistent across accreditation records, reports, certificates, and public communications.

Guidance on accreditation claims

Treatment of Activities Outside Scope

Differentiate clearly accredited activities from services that fall outside the approved scope, protecting customers from misleading claims.

  • Specify non-accredited activities clearly in mixed-service reports and promotional material.
  • Ensure accreditation claims exclude activities, locations, and certification schemes that have not been assessed.

Reports and symbol usage

Use of Accredited Certificates and Reports

Prepare certificates and reports that accurately identify the conformity assessment activity and the accreditation status of the results presented.

  • Use the relevant standard's reporting requirements and identify the issuing organization and authorized signatories as required.
  • Apply accreditation symbols only in accordance with QAC usage rules and the approved scope.

02 / Assessment pathways

Guidance on program-specific guidelines

Principal assessment considerations for six conformity assessment disciplines, from application and document review to on-site evaluation, accreditation decisions, and ongoing surveillance.

ISO/IEC 17021-1

Management System Certification Bodies

Guidance addressing the accreditation pathway for bodies that audit and certify management systems.

  • Prepare for application review, documentation assessment, office evaluation, and witnessed audits.
  • Demonstrate auditor competence, impartial review and decisions, effective certification controls, and surveillance.

ISO/IEC 17025

Testing and Calibration Laboratories

Assessment guidance for laboratories demonstrating the competence and consistency of their testing and calibration activities.

  • Record review, on-site assessment, method verification or validation, and technical records.
  • Demonstrate equipment control, evaluation of measurement uncertainty, metrological traceability, and continuing assurance of valid results.

ISO/IEC 17065

Product Certification Bodies

Guidance intended for bodies certifying products, processes, and services against defined certification scheme requirements.

  • Demonstrate conformity with scheme requirements through evaluation activities and applicable witnessing.
  • Maintain competent personnel, independent review and certification decisions, and scheme-specific surveillance.

ISO/IEC 17020

Inspection Bodies

Assessment guidance for Type A, B, and C inspection bodies, with emphasis on independence and consistent inspection outcomes.

  • Verify independence arrangements and demonstrate the competence of inspection personnel.
  • Maintain inspection procedures, enable witnessed inspections, and demonstrate reporting and surveillance controls.

ISO/IEC 17024

Personnel Certification Bodies

Guidance intended for organizations certifying individuals against established competence requirements and certification schemes.

  • Document scheme development and maintenance, candidate eligibility, and applicable witness evaluations.
  • Protect examination security and maintain valid assessment methods, impartial decisions, and recertification controls.

ISO 15189:2022

Medical Laboratories

Technical guidance for medical laboratory quality and competence, with patient safety central to the assessment of laboratory services.

  • Evaluate the complete examination pathway, from specimen handling through examination to result reporting.
  • Personnel competence, quality assurance, risk management, and patient-focused service delivery; ask QAC to confirm program availability.

03 / Measurement & quality assurance

Guidance on technical guidance

Operational considerations for laboratories and reference material producers (RMPs), addressing uncertainty, traceability, proficiency testing, and the United States' measurement infrastructure.

Guidance on uncertainty evaluation

Measurement Uncertainty Guidance

Assess and communicate measurement uncertainty using approaches appropriate to the method, measurement process, and intended use of the result.

  • Specify significant uncertainty contributions and maintain documented evaluation methods.
  • Use relevant estimation and reporting requirements for calibration, testing, and reference material production.

Guidance on metrological traceability

Measurement Traceability Policy

Determine traceability to the International System of Units (SI), where technically possible, through a documented, unbroken chain of calibrations.

  • Consider measurement uncertainty at each stage and verify calibration provider competence.
  • When traceability to SI is technically unavailable, select appropriate accepted references and document the justification.

Guidance on external performance assurance

Proficiency Testing Policy

Apply proficiency testing and suitable interlaboratory comparisons to monitor performance and support confidence in technical results.

  • Prepare for participation in relation to the accredited scope, technical risks, and availability of suitable programs.
  • Assess results using appropriate statistical methods, investigate unsatisfactory performance, and verify corrective-action effectiveness.

NIST and national measurement framework

US Metrological Infrastructure

Examine the role of the National Institute of Standards and Technology (NIST) in the United States' measurement infrastructure and national traceability framework.

  • Identify national measurement standards, calibration services, and standard reference materials suitable for your activities.
  • Show traceability through documented evidence; a reference to NIST alone does not establish a traceable measurement result.

Document requirements and clarification

Ask QAC about current requirements, document editions, transition arrangements and program availability. Identify your program and proposed or approved scope so the enquiry can be reviewed in its technical context.

Contact QAC

Using this guidance

These summaries supplement, but do not replace, applicable standards, formal accreditation policies and program requirements. References to IAF, ILAC and NIST provide technical context only; they do not imply QAC membership, endorsement or recognition.

Guidance on standards transitions

Managing transitions to revised standards

Coordinate changes to applicable standards through a documented transition plan that maintains competence and continuity of accredited activities.

Determine the applicable transition arrangements

Changes to management system standards, including ISO 9001 and ISO 14001, and laboratory standards, including ISO/IEC 17025 and ISO 15189, may call for coordinated implementation. Verify the official transition decision, relevant edition, completion date, and assessment arrangements for the particular scheme. A single transition period should not be presumed for all standards.

Show effective implementation

Develop a gap analysis, revise the management system, update operational processes and controlled documents, and establish the competence needed for the revised requirements. Assessment evidence should show both understanding of the changes and effective implementation, not only revised documentation.

Plan certificate changes

Certification bodies should plan the transition of affected client certificates alongside their own accreditation arrangements. Examine certificate wording and validity against the applicable transition decision. Verify the treatment of accreditation or certificates that have not transitioned by the deadline with QAC; do not continue unsupported claims to a superseded edition.

Verify current document editions and program requirements with QAC. Citing an international publication does not establish membership, recognition or permission to use arrangement marks.

Guidance on scope definition

Guidance on defining and maintaining an accurate scope

Describe the scope of accreditation with sufficient clarity and precision to identify the activities for which competence has been demonstrated.

Set out demonstrated competence

The approved scope identifies the activities covered by accreditation. Provide precise technical descriptions that customers and other stakeholders can understand, including applicable standards, methods, parameters, ranges, service categories, locations, and limitations. Avoid promotional language, broad unsupported descriptions, and activities that have not been assessed.

Manage changes and public representations

Examine the scope when activities are added or discontinued, methods or standards change, or the organization's name, structure, or operating locations change. Obtain approval for extensions before representing the additional work as accredited. Maintain a current scope record and confirm the approved arrangements for making it available to customers and the public.

Develop a clear submission

Check that application information, technical records, certificates, reports, and website claims describe the same approved activities. Resolve ambiguous wording and outdated references before submission. Ask QAC for clarification where a proposed scope needs technical interpretation.

Verify current document editions and program requirements with QAC. Citing an international publication does not establish membership, recognition or permission to use arrangement marks.

Guidance on accreditation claims

Guidance on separating accredited and non-accredited services

Differentiate clearly accredited activities from services that fall outside the approved scope, protecting customers from misleading claims.

Avoid organization-wide implications

Organizations may undertake both accredited and non-accredited work. Website statements and marketing material should explain that accreditation applies only to the activities identified in the approved scope. Laboratories and certification bodies should not suggest that every test, method, scheme, or service they offer is accredited.

Specify status in mixed reports

Where a report includes work with different accreditation status, use an unambiguous statement or clearly explained marking system to identify the accredited results. Ensure that any asterisk or legend is explained and does not create uncertainty about the status of individual results. Do not attach an accreditation symbol to a standalone non-accredited deliverable.

Guidance on illustrative disclosure and continuing review

An appropriate disclosure may explain that accreditation covers only the activities listed in the organization's approved scope and that other services are outside that scope. Adapt the statement to the actual services rather than copying an example certificate number or company name. Check claims during internal checks and assessment preparation, correct misleading statements promptly, and consult QAC's applicable policies for any formal consequences.

Verify current document editions and program requirements with QAC. Citing an international publication does not establish membership, recognition or permission to use arrangement marks.

Reports and symbol usage

Guidance on issuing credible certificates and technical reports

Prepare certificates and reports that accurately identify the conformity assessment activity and the accreditation status of the results presented.

Core identification and authorization

Follow the relevant standard's requirements for the issuer's legal identity and address, a unique document identifier, identification of the assessed activity and applicable standard or method, issue date, any applicable validity period, and authorized approval. Accreditation references and symbols must accurately reflect the issuing body's status and approved scope.

Guidance on laboratory-specific reporting

Where applicable, identify the examined items, methods, results and units, measurement uncertainty, relevant environmental conditions, and persons responsible for technical approval. Include statements of conformity only where appropriate and document the agreed decision rule. Distinguish a client's certification from the certification body's own accreditation.

Guidance on symbols, electronic records, and templates

Use only symbols for which the organization has documented authorization, without unauthorized alteration. IAF MLA or ILAC MRA marks are not automatically available through accreditation; any use requires verified entitlement and the relevant agreement. Protect electronic certificates and reports against unauthorized changes through suitable approval controls, secure delivery, or digital signatures. Verify any template-review requirements with QAC before use.

Verify current document editions and program requirements with QAC. Citing an international publication does not establish membership, recognition or permission to use arrangement marks.

ISO/IEC 17021-1

Guidance on management system certification assessment

Guidance addressing the accreditation pathway for bodies that audit and certify management systems.

Guidance on application and assessment planning

Define the requested certification schemes, standards, sectors, and scope. Compile the quality manual, operational procedures, competence matrix, and evidence of impartiality arrangements. Application review considers eligibility and assessment resources before agreement on the assessment arrangements and appointment of a suitably competent team.

Record review, office assessment, and witnessing

Examine the management system against ISO/IEC 17021-1 and applicable scheme-specific competence requirements. Assessment examines impartiality, personnel competence, audit planning and delivery, certification decisions, and control of records. Witnessed audits provide evidence of the body's ability to carry out certification work in the requested technical sectors.

Guidance on closure, independent decision, and continued accreditation

Resolve findings with objective evidence of correction and corrective action before independent accreditation review. The approved decision defines the scope and any conditions of accreditation. Continued accreditation follows QAC's four-year cycle with annual surveillance and reassessment. Examples of management system disciplines include quality, environment, occupational health and safety, information security, compliance, anti-bribery, business continuity, energy, medical devices, and artificial intelligence; confirm the applicable competence standards and scope for each scheme.

Verify current document editions and program requirements with QAC. Citing an international publication does not establish membership, recognition or permission to use arrangement marks.

ISO/IEC 17025

Guidance on testing and calibration laboratory assessment

Assessment guidance for laboratories demonstrating the competence and consistency of their testing and calibration activities.

Specify the laboratory's technical scope

Determine whether the application covers testing, calibration, or both. Specify methods, parameters, ranges, locations, and measurement capabilities. Supporting information should include the management system, method list, relevant calibration ranges, and evidence of proficiency testing or suitable interlaboratory comparisons.

Examine technical practice and valid results

Record review and on-site evaluation examine conformity with ISO/IEC 17025. Assessors consider method verification and validation, measurement uncertainty, metrological traceability, equipment control, staff competence, and technical records. Observation of laboratory work and personnel interviews support evaluation of the laboratory's actual performance.

Accreditation decisions and continuing assurance

Close assessment findings with verified evidence before an independent accreditation decision. Ensure the issued scope accurately identifies the approved activities. Maintain performance assurance and prepare for annual surveillance and reassessment within QAC's four-year accreditation cycle.

Verify current document editions and program requirements with QAC. Citing an international publication does not establish membership, recognition or permission to use arrangement marks.

ISO/IEC 17065

Guidance on product, process, and service certification assessment

Guidance intended for bodies certifying products, processes, and services against defined certification scheme requirements.

Certification schemes and assessment preparation

Set out the products, processes, or services to be certified, the applicable scheme requirements and standards, the evaluation procedures, and personnel competence. Application and agreement stages establish the proposed scope and assessment resources. Document review considers the management system, impartiality safeguards, and the operation of certification schemes under ISO/IEC 17065.

Assess certification activities

Office assessment reviews records, personnel competence, scheme operation, and independent review and decision-making. Witness evaluations may cover actual certification audits, inspections, testing oversight, or product evaluation, according to the nature of the scheme. Remote assessment arrangements, if proposed, require confirmation of suitability.

Keep scheme compliance

Provide evidence addressing findings before accreditation review. Ongoing surveillance examines continuing conformity and relevant certification activities; the witnessing plan depends on the approved program and risks. Notify changes to schemes or scope and confirm whether supplementary assessment is required. QAC's cycle is four years with annual surveillance.

Verify current document editions and program requirements with QAC. Citing an international publication does not establish membership, recognition or permission to use arrangement marks.

ISO/IEC 17020

Guidance on inspection competence and independence assessment

Assessment guidance for Type A, B, and C inspection bodies, with emphasis on independence and consistent inspection outcomes.

Specify the inspection body's independence type

ISO/IEC 17020 distinguishes Type A third-party inspection bodies, Type B bodies serving their parent organization, and Type C bodies with safeguards for inspection services provided to their own or other organizations. Define the appropriate type and demonstrate the corresponding independence arrangements. Scope descriptions may cover materials, products, installations, plants, processes, procedures, services, or design.

Evaluate field work and reporting

Compile the management system, inspection methods, requested scope, and personnel competence evidence. Document and on-site reviews examine facilities, equipment, calibration, sample reports, traceability where applicable, and report integrity. Witnessed inspections evaluate the practical application of methods, objective judgment, appropriate equipment, and accurate reporting at relevant field or client locations.

Accreditation decisions and surveillance

Resolve findings with verified corrective-action evidence before independent review. Approved records should clearly identify the inspection scope and independence type. Maintain competence and independence through annual surveillance and planned witnessing, with reassessment in QAC's four-year cycle. Scope changes may require supplementary evaluation.

Verify current document editions and program requirements with QAC. Citing an international publication does not establish membership, recognition or permission to use arrangement marks.

ISO/IEC 17024

Guidance on personnel certification scheme assessment

Guidance intended for organizations certifying individuals against established competence requirements and certification schemes.

Specify competence and examination arrangements

Applications should set out the occupational or professional schemes, competence criteria, eligibility requirements, assessment methods, and proposed scope. ISO/IEC 17024 assessment considers scheme development and maintenance, examination design, examiner competence, impartiality, and the independence of certification decisions.

Safeguard candidate records and examination integrity

Evaluation reviews candidate records, examination administration, confidentiality and security, recertification, and handling of appeals and complaints. Witnessing of live examinations or practical assessments can demonstrate consistent application of criteria, protection of confidential material, and impartial decisions.

Examine and maintain certification competence

Check correction and corrective-action evidence before independent accreditation review. The approved scope identifies the covered certification schemes. Plan continuing surveillance and relevant witness activities, and notify scheme additions or removals. QAC uses a four-year accreditation cycle with annual surveillance.

Verify current document editions and program requirements with QAC. Citing an international publication does not establish membership, recognition or permission to use arrangement marks.

ISO 15189:2022

Guidance on medical laboratory quality and patient safety

Technical guidance for medical laboratory quality and competence, with patient safety central to the assessment of laboratory services.

Guidance on clinical services and application information

ISO 15189:2022 addresses medical laboratory quality and competence. Relevant settings include hospital, reference, specialty, and point-of-care services. Clinical disciplines may include chemistry, hematology, microbiology, molecular biology, immunology, and pathology. Preparation includes the management system, examination list, equipment inventory, staff qualifications, and proposed clinical scope. Verify QAC program availability before applying.

Assess the complete examination pathway

Pre-examination processes include patient preparation, specimen collection, and handling. Examination activities encompass the analytical process; post-examination activities include result review, reporting, interpretation, and consultation. Assessment considers method validation, quality control, personnel competence, calibration, traceability, confidentiality, proficiency testing, and uncertainty where relevant, with patient safety and clinical relevance throughout.

Guidance on witnessing and continued oversight

Witness evaluation may be suitable to demonstrate clinical and technical competence. Resolve findings before independent review of the requested examination categories. Confirm surveillance, reassessment, and supplementary evaluation arrangements when examinations or locations change; any QAC accreditation cycle follows the four-year cycle with annual surveillance.

Verify current document editions and program requirements with QAC. Citing an international publication does not establish membership, recognition or permission to use arrangement marks.

Guidance on uncertainty evaluation

Guidance on evaluating and reporting measurement uncertainty

Assess and communicate measurement uncertainty using approaches appropriate to the method, measurement process, and intended use of the result.

Principles of uncertainty evaluation

The relevant reference framework includes ISO/IEC 17025, ISO 17034, the Guide to the Expression of Uncertainty in Measurement (JCGM 100), and applicable ILAC guidance. Method-specific requirements take precedence. Type A evaluation uses statistical analysis of observations; Type B evaluation uses other evidence such as calibration data, specifications, resolution, or established experience. Identify significant contributions, justify distributions, and account for correlations where relevant.

Guidance on calibration and testing applications

A calibration uncertainty budget may include reference-standard uncertainty and drift, instrument resolution, repeatability, environmental conditions, setup, and measurement-model effects. Combine contributions using an appropriate model and derive expanded uncertainty with a justified coverage factor and coverage statement. Testing evaluations may also include sample preparation, matrix effects, recovery, precision, bias, and validation evidence. For qualitative methods, document whether numerical uncertainty is meaningful rather than forcing an unsuitable calculation.

Guidance on reference materials and communication

In reference material production, evaluate characterization, homogeneity, stability, and transport or storage influences as applicable. Reports should identify the result and units, uncertainty where required, coverage factor or probability, and the basis of evaluation. Explain how uncertainty is considered in conformity decisions, including any agreed guard band or risk-based decision rule. Worked evaluations should use the actual measurement model and data, rather than treating a generic caliper, chloride, or reference-material example as a universal budget.

Verify current document editions and program requirements with QAC. Citing an international publication does not establish membership, recognition or permission to use arrangement marks.

Guidance on metrological traceability

Guidance on establishing defensible metrological traceability

Determine traceability to the International System of Units (SI), where technically possible, through a documented, unbroken chain of calibrations.

Choose an appropriate traceability route

ISO/IEC 17025 and ISO 17034 address traceability relevant to laboratory work and reference material production; consult the current applicable ILAC policy. Traceability to SI may be supported by suitable services from national metrology institutes, competent accredited calibration laboratories, or appropriate certified reference materials. Verify the relevant capability, scope, and recognition arrangements rather than relying on a provider's name alone.

Keep evidence throughout the chain

Record the hierarchy for each relevant parameter and range, the calibration provider, equipment identification, calibration results and uncertainty, and the basis for calibration intervals. For example, a weighing result may link through calibrated weights and national mass standards to the SI kilogram. Review calibration intervals using equipment stability, use, environmental conditions, and relevant recommendations.

Check and address gaps

At appropriate intervals, review certificates, traceability chains, and uncertainty budgets to ensure they support the intended measurements. Where SI traceability is technically unavailable, establish an appropriate accepted reference and explain the justification. Investigate missing or unsuitable evidence and document the action taken to restore confidence in the affected measurements.

Verify current document editions and program requirements with QAC. Citing an international publication does not establish membership, recognition or permission to use arrangement marks.

Guidance on external performance assurance

Guidance on planning proficiency testing and performance follow-up

Apply proficiency testing and suitable interlaboratory comparisons to monitor performance and support confidence in technical results.

Develop a scope-based participation plan

Apply relevant requirements from ISO/IEC 17025, the current ISO/IEC 17043 framework, applicable ILAC guidance, and suitable statistical methods such as ISO 13528. Select testing or interlaboratory comparison activities that represent the laboratory's disciplines, matrices, methods, and ranges. Set participation frequency according to applicable requirements, technical risk, and scheme availability; confirm any mandatory interval with QAC.

Assess results appropriately

Apply the scheme's assigned values and evaluation criteria. A z-score compares the result's deviation from the assigned value with the proficiency-assessment standard deviation. An En value compares the result difference with the combined reported expanded uncertainties, subject to the scheme's assumptions. Other approaches, including Youden plots, may help identify performance patterns. Apply the provider's justified acceptance criteria rather than assuming one statistical method suits every activity.

Guidance on investigate, correct, and retain evidence

Examine the report, identify unsatisfactory outcomes, investigate root causes, implement corrections and corrective actions, and verify effectiveness. Retain the participation plan, original results, evaluation, investigation, and follow-up evidence available for assessment under the applicable record-retention requirements. Where a suitable scheme is unavailable, document the limitation and discuss an appropriate alternative with QAC.

Verify current document editions and program requirements with QAC. Citing an international publication does not establish membership, recognition or permission to use arrangement marks.

NIST and national measurement framework

Guidance on understanding the US measurement infrastructure

Examine the role of the National Institute of Standards and Technology (NIST) in the United States' measurement infrastructure and national traceability framework.

Guidance on national standards and technical services

NIST maintains national measurement capabilities as part of the US Department of Commerce. It was established in 1901 as the National Bureau of Standards. Its work includes measurement standards, calibration services, standard reference materials and data, and the National Voluntary Laboratory Accreditation Program (NVLAP). Major NIST locations include Gaithersburg, Maryland, and Boulder, Colorado.

Guidance on international equivalence and traceability

The international measurement framework comprises the BIPM, the CIPM Mutual Recognition Arrangement, regional metrology organizations such as the Inter-American Metrology System (SIM), and published calibration and measurement capabilities in the BIPM Key Comparison Database. Comparisons support evidence of measurement equivalence. A suitable traceability chain may connect national standards through competent calibration providers to laboratory and industrial measurements.

Guidance on legal metrology and the wider ecosystem

NIST's Office of Weights and Measures and the National Conference on Weights and Measures support the US legal-metrology system alongside state authorities. Industry, private laboratories, universities, and agencies including the Department of Defense, Department of Energy, and NASA contribute to measurement capability in sectors such as aerospace, energy, healthcare, and semiconductors. National standards, calibration providers, measurement users, and state enforcement authorities perform distinct roles; this US-focused overview does not describe every North American jurisdiction or establish a QAC affiliation.

Verify current document editions and program requirements with QAC. Citing an international publication does not establish membership, recognition or permission to use arrangement marks.