For ISO/IEC 17025, method validation is a key requirement to deliver meaningful data.
Standard and in-house methods need validation and verification.
Likewise, validation is a planned activity that encompasses parameters. Meanwhile, validation is incomplete if there’s no statement of fitness for purpose.
In this article, QSE Academy explains the requirements and necessities of method validation for the success of your ISO 17025 implementation.
What is Validation?
ISO/IEC 17025 defines validation as “the confirmation by examination and the provision of objective evidence that the particular requirements for specific intended use are fulfilled”.
Validation is specifically intended to be used as an analytical requirement. Does it answer questions such as why are measurements necessary? What test method will be used?
Therefore, there can be no assurance that results will be suitable for purpose if there’s no validation.
Validation also serves as objective evidence because it becomes information on method performance. Similarly, it is a method validation study’s experimental data.
Finally, confirmation is involved because there must be a comparison of requirements with experimental evidence.
What is Method Validation?
Method validation is the system that confirms whether the analytical procedure used for a certain test is appropriate for its intended use.
Likewise, method validation is a crucial aspect of any good analytical practice.
Analytical methods must be authenticated or revalidated before their introduction into routine use.
Method validation also applies whenever the conditions change for which the method has been validated. Lastly, this is also done whenever the process is changed, especially if the change is outside the method’s original scope.
Hence, the results can be utilized to critic the consistency, reliability, and quality of analytical results.
Extent of Validation
Generally, validation should be as wide-ranging as needed for the application. Also, it must record document procedures and validation data.
Laboratories must always remember to include the statement ‘fitness for purpose’.
Note that method performance must be significant to customer needs. It must also be evaluated against the intended use of the method.
What is Fitness for Purpose?
Fitness for purpose means analyzing data using method performance parameters.
It identifies whether laboratories can achieve target values. If yes, then the method is fit for purpose. If not, then laboratories would require more development.
How to Prove a Particular Method’s Validity?
- Analyze laboratory experiments using standards or samples that are akin to unknown samples.
- Create a validation protocol that includes a step-by-step instruction format.
- Include the procedure that shows:
- The chosen instrument;
- The developed method;
- Ease of use;
- Ability to be automated and to be controlled by computer systems;
- Sample throughput;
- Turnaround time;
- Costs per analysis;
- Safety requirements;
- Environmental requirements;
- Health requirements.
The Importance of Method Validation
As mentioned earlier, method validation is a vital requirement of ISO/IEC 17025.
More than that, it serves as a system to guarantee the reliability of results.
Additionally, method validation equates to the constant application of methods. Also, it means better agreement among nations, laboratories, and analysts.
When Can Laboratories Validate a Method?
First, laboratories can validate a method before using any method for test sample analysis.
It includes published and/or standard methods that have been validated by others.
In this way, laboratories can verify the capability to match published data, as well as appropriateness for the analytical requirement.
Secondly, laboratories could conduct method validation during method development. As a result, it can be verified if the proposed method is fit for purpose.
Finally, laboratories could execute method validation following a period of non-use or when there’s a change of working environment, analyst, and application.
ISO/IEC 17025 Selection of Methods and Method Validation
- 4.1 General
This section states that a laboratory must use the proper procedures and for all tests within its scope.
- 4.2 Selection of methods
This section entails that a laboratory must confirm it can correctly operate standard methods before introducing the tests.
Furthermore, methods shall fulfill customer requirements.
The selection of methods must have a preference for both local and global standard method.
However, laboratory-developed methods can be used if they are validated.
5.4.5 Validation of Methods
This section includes types of methods that need validation such as standard, non-standard, laboratory-developed/designed, modified/amplified standard methods, and standard methods outside the normal scope.
This also covers mandatory validation to show that methods are apt for their intended use.
Describing the Analytical Requirement
- Laboratories must determine the required measurements, as well as what will the data be used for.
- Laboratories shall classify the size and nature.
- Laboratories must identify whether to use qualitative or quantitative.
- Laboratories need to define the likely concentration or the total/available class and species.
- Laboratories should detect other considerations such as timescale, destructive test, and non-destructive test.
Method Performance Parameters
- Precision – This determines repeatability and reproducibility. It also identifies the similarities of replicate measurements results made on a similar sample.
- Working Range – It is the range of concentrations that can be measured reliably. It also covers the limit of quantitation and detection.
- Selectivity/Specificity – It confirms whether there any interferences. It also defines whether laboratories are measuring what they think they are measuring.
- Bias/Trueness – This identifies how close are the results of the correct answer.
- Ruggedness/Robustness – It provides control vital for the procedure’s stages.
How Much Validation?
Validation depends on the criticality of the measurements, available experience, level of information, and the method’s scope.
|PARAMETER||TYPE OF ANALYSIS|
|Qualitative||Physical Property||Major Component||Trace Analysis|
|Limit of Detection||Yes||No||No||Yes|
|Limit of Quantitation||No||No||No||Yes|
As explained earlier, method validation is a planned activity. Thus, your laboratory must plan carefully before conducting method validation.