What is the difference between method validation and verification?
- Method validation is a demonstration of the method suitability by determining an accuracy of the test results as well as an uncertainty and a traceability of measurements. Method validation is needed for proving whether new method is fit for purpose or specified samples.
- Verification is a confirmation whether a test method fulfills the specified requirements by inspecting the given items in the test method and preparing the related documentation. Therefore, the verification is applied for the method which has been validated (or the standard method) The verification is usually carried out by comparing the performance data of the laboratory in many aspects such as the technical competence of the staff, the equipments, and the environmental conditions.
- Method validation shall be done when the method is
o Non-standard method
o Developed method
o Standard method used outside its intended scope of Modified method
o Portable test instruments and test kits
When some changes are made in the validated non-standard methods, the influence of such changes should be documented and, if appropriate, a new validation should be carried out. Some changes in the method include:
o difference of the interferences in the test sample.
o difference of the test methods such as drying time, distillation, incubation, temperature / criteria.
o development or modification of the methods such as the substances and media used in the methods.
o decrease in the step of analysis such as time, amount of the substance.
o reduction or elimination of the retest in order to save the cost.