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Methods verification

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Guest user Created:   Apr 29, 2020 Last commented:   Apr 30, 2020

Methods verification

I would like to ask you about methods verification (we have implemented standard methods), so we don't have to validate them but only verified. Which parameters will be verified for standard methods? About quality data control, which procedure can you suggest to me?

If you have some examples or some specific information about that and if you can send me something I will thank you very much.

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ISO 17025 DOCUMENTATION TOOLKIT

Step-by-step implementation for smaller companies.

ISO 17025 DOCUMENTATION TOOLKIT

Step-by-step implementation for smaller companies.

Expert
Tracey Evans Apr 30, 2020

You asked

Which parameters will be verified for standard methods?

Verification of a standard method means that you are in fact confirming that your laboratory can achieve the expected (reported) performance of the standardised method. i.e. you are justified to apply that standard method for your purpose. In certain sectors the parameters are defined in regulations or guidelines. There are, in principle a number of parameters that are used as measure of performance. These include, but not solely, bias; selectivity; measurement range with limit of linearity, limit of detection and limit of quantification; ruggedness (robustness); and measurement uncertainty.

The parameters depend on the technique and intended use the test result. For example pH and GC-MS or HPLC by their principle will have different performance parameters.

Published standardised procedures would already be validated  for given matrix types and working range. The intended use, i.e. your laboratory’s application of the standard method must be considered. In the context of ISO 17025 technical competency assessment, all these parameters should be evaluated unless you are justified not to. This means that, for example, your laboratory would not need to do experimentation to show selectivity of a chromatography column and ruggedness if used within the scope of the method. However if you the matrix was ,say an unfiltered wine and the standard method did not cover this matrix in the studies, you would have to assess the effect of possible interferences

You also asked

About quality data control, which procedure can you suggest to me?

Here again it depends on the technique and purpose of the test. For example there may be instrument fluctuations and the results could be subject to the sensitivity of the method. The controls must be chosen considering the risks to maintaining consistent performance of your validated method. 
Various monitoring measures can be made to trend random and systematic errors; for example the use of Quality control charts. Internal controls can include analysing replicate samples, various blanks (sample and reagent blanks), reference standards, spiked solution or material, and inhouse control material (of well-defined analytes of interest) in the same batch analysis as unknown samples.

 

Have  a look at the ISO 17025 toolkit at https://advisera.com/17025academy/iso-17025-documentation-toolkit/. It includes the procedure for validation and verification of methods, named Test and Calibration Method Procedure, along a Test Method Development, Verification and Validation Register and Test Method Development, Verification and Validation Record. The techniques for method validation are listed as well as the required records. It is the responsibility of the laboratory to choose the suitable technique, plan experiments, reference sector specific guidelines and meet specific regulatory and accreditation body requirements. The procedure is also available separately at https://advisera.com/17025academy/documentation/test-and-calibration-method-procedure/

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