Process Requirements for Consistent Results in ISO/IEC 17025

Laboratory testing plays a crucial role in ensuring the safety and quality of our food supply. Behind every food product on store shelves, countless samples have been analyzed to verify they meet safety standards. ISO/IEC 17025 serves as the global standard for laboratory competence, with process requirements forming its operational backbone. These requirements ensure that testing procedures deliver consistent, accurate, and reliable results-regardless of who performs the testing or when it occurs.

Understanding process requirements in laboratory operations 🔗

Process requirements form the operational framework that dictates how laboratories conduct their daily activities. ISO/IEC 17025:2017 details 11 key processes that laboratories must implement to improve efficiency and ensure consistent results. These requirements cover everything from reviewing requests to issuing reports, creating a systematic approach that ensures quality at every stage.

Think of process requirements as the laboratory’s operational manual. They provide step-by-step instructions that, when followed correctly, yield reliable results consistently. The standard requires laboratories to demonstrate they operate competently and generate valid results, promoting confidence in their work both nationally and internationally.

Method selection, verification, and validation 🔗

One of the most critical process requirements involves how laboratories choose and confirm their testing methods. Method validation proves that an analytical method is suitable for its intended purpose, while verification confirms that an already validated method performs adequately within a specific laboratory environment.

Method validation is required when laboratories develop new methods, significantly modify existing ones, or use non-standard approaches. This comprehensive process evaluates multiple performance parameters including accuracy, precision, specificity, detection limits, and linearity. Laboratories must document evidence that the method consistently produces reliable results under defined conditions.

Method verification applies when adopting standard methods developed by organizations like ISO, ASTM, or AOAC. Verification confirms that a laboratory can achieve the established performance characteristics defined during method validation. Parameters requiring verification include repeatability and reproducibility, though certain characteristics like linearity do not vary between laboratories and therefore do not require reverification.

Documentation and performance assessment 🔗

Both validation and verification activities must be thoroughly documented. Records should include the method used, the assessment plan, evaluation results, and the final decision confirming the method’s suitability. This documentation demonstrates that every test or calibration is based on methods proven in practice, not just theoretically valid.

Sampling procedures and traceability 🔗

Sampling represents a critical step in the testing process because everything that follows depends on it. If samples are not collected correctly, test results lose their meaning regardless of how sophisticated the laboratory’s methods or equipment may be.

ISO/IEC 17025:2017 requires laboratories to have documented sampling plans and methods when sampling substances, materials, or products for testing or calibration. These procedures must address factors that ensure the validity of subsequent testing.

A complete sampling procedure includes the purpose of sampling, the sampling plan detailing how much and how often samples are taken, the specific sampling method with tools and techniques, and instructions for handling and storage. Recordkeeping is equally important. Every sample must be clearly linked to its corresponding test through proper labeling, logging, and traceability throughout the process.

Records should document who collected the sample, when and where it was collected, relevant environmental conditions, and any deviations from planned procedures. This level of detail ensures laboratories can trace results back to their source and prove that sampling was conducted in a controlled, repeatable manner.

Handling test and calibration items 🔗

Proper handling of items received for testing directly affects result reliability. ISO/IEC 17025 establishes clear expectations for transportation, storage, and tracking of all incoming materials.

Laboratories must ensure every item is uniquely identified using labels, barcodes, or tracking numbers. Upon receipt, the condition must be checked and any damage documented. Items require proper storage to prevent deterioration, contamination, or confusion. The handling process must maintain traceability from receipt through final reporting.

For instance, biological samples requiring refrigeration must be logged in promptly and stored at proper temperatures. Delays or improper storage compromise results and damage client trust. Procedures should also address separating similar samples, managing hazardous materials, and handling extended storage requirements.

Ensuring validity through quality control 🔗

Laboratories must continuously monitor their performance to confirm methods deliver reliable results. ISO/IEC 17025 requires procedures for monitoring result validity, including regular use of reference materials, alternative instrumentation for result confirmation, functional checks of measuring equipment, and intermediate verification between calibrations.

Quality control measures serve as the laboratory’s immune system, detecting issues before they impact results. Control charts track performance over time, replicate testing checks consistency, and blank tests detect contamination or bias. These activities must be performed regularly with results used to adjust processes when needed.

External validation through proficiency testing 🔗

Participation in proficiency testing or interlaboratory comparisons provides independent assessment of laboratory performance. In these programs, identical samples are distributed to multiple laboratories for testing, with results compared to determine accuracy. For example, a laboratory testing for pesticide residues might participate in national proficiency schemes where all labs receive spiked samples and must detect and quantify target compounds. Results outside acceptable limits trigger investigation and corrective action.

Technical records and measurement uncertainty 🔗

Complete technical records tell the full story behind each result. ISO/IEC 17025 requires laboratories to maintain records including item identification, dates and times of activities, personnel who performed tasks, equipment and software used, environmental conditions affecting results, all observations and calculations, and any deviations or corrections made during testing.

This detail level allows anyone to trace results back through every process step. When clients ask how results were obtained, laboratories should provide clear records explaining each step without gaps or guesswork.

Measurement uncertainty represents another critical consideration. Laboratories must identify contributions to uncertainty, evaluating all significant factors including those arising from sampling. When performing calibrations, laboratories evaluate their own equipment for uncertainty. For testing, measurement uncertainty evaluation is required unless test methods exclude rigorous assessment, in which case estimates based on theoretical principles or practical experience are made.

Reporting results with clarity 🔗

Test reports communicate findings to clients and must be clear, complete, and meaningful. Reports should include unique identifiers, laboratory and client information, item descriptions, receipt and testing dates, methods used, and results clearly presented with authorization.

The 2017 standard revision introduced requirements for decision rules when making statements of conformity like pass or fail determinations. Decision rules define how uncertainty is considered when determining if results meet specified requirements. These rules must be defined before testing and agreed upon with clients when applicable. For example, when results must meet regulatory limits, decision rules clearly state how measurement uncertainty factors into pass or fail decisions.

Managing complaints and nonconformities 🔗

Even well-run laboratories encounter issues. ISO/IEC 17025 expects laboratories to handle complaints and nonconformities professionally and transparently. Laboratories must have documented processes for receiving, evaluating, and resolving complaints.

When nonconforming work occurs-such as failed controls, procedural errors, or unexpected results-laboratories must detect and record the issue, stop or withhold affected work if necessary, evaluate impacts on tested items and clients, take corrective action, and document everything thoroughly. The standard expects accountability rather than perfection.

Data integrity and information management 🔗

Controlling data represents one of the most important process requirements in modern laboratories. ISO/IEC 17025 requires that data be protected from unauthorized access, alteration, or loss. Regular backups must be performed with recovery plans in place. Access controls ensure only authorized personnel make changes, and electronic systems must be validated for accuracy. Changes to data require tracking through audit trails.

Whether laboratories use paper-based systems or fully digital platforms, controls must be consistent and documented. For example, spreadsheet-based systems need password protection, approved version control, change logging, and secure backup storage. These requirements apply to both raw data from instruments and final results shared with clients.

What do you think? How does your laboratory currently ensure consistency across all process requirements? Are there areas where improved documentation or quality control measures could strengthen your testing operations?

References

1. https://www.iso.org/ISO-IEC-17025-testing-and-calibration-laboratories.html
2. https://safetyculture.com/topics/iso-17025
3. https://www.qse-academy.com/purpose-of-iso-17025-method-validation/
4. https://www.labservcenter.com/en/2024/06/27/how-to-meet-iso-17025-requirements-for-method-verification/
5. https://17025store.com/iso-iec-17025-2017-requirements/clause-7-process-requirements/
6. https://qbench.com/blog/iso-17025-everything-labs-need-to-know
7. https://www.qse-academy.com/process-requirements-of-iso-17025/