PRIORITY business intelligence

The general requirements that testing and calibration laboratories have to meet if they wish to demonstrate that they operate to a quality system, are technically competent and are able to generate technically valid results are contained within ISO/IEC 17025:2005. One of the main requirements of the ISO/IEC 17025:2005 is use of validated or verified methods.

A method should be validated when it is necessary to verify that its performance parameters are adequate for use for a particular analytical problem. For example:

• new method developed for particular problem;
• established method revised to incorporate improvements or extended to a new problem;
• when quality control indicates an established method is changing with time;
• established method used in a different laboratory, or with different analysts or different
• instrumentation;
• to demonstrate the equivalence between two methods, e.g. a new method and a standard.

When a method is verified, the laboratory is required to demonstrate that it can achieve certain specific performance characteristics/parameters established during the validation study. The validation study must contain all pertinent performance characteristics. Certain performance characteristics, such as linearity, will not vary from lab to lab and do not need to be verified. Other parameters, such as repeatability, are specific to the lab performing the method and need to be verified. Thus, the performance characteristics that need to be verified are a subset of the performance characteristics included in a method validation.

Performance Characteristics Included in a Validation:

• Accuracy
• Precision
• Specificity
• LOD (Limit of Detection)
• LOQ (Limit of Quantitation)
• Ruggedness
• Linearity/Range