Following the previous webinar, in this part Dr. Roy Betts will explain method validation and verification of microbiological test methods, and how they differ. It outlines what you need to do for a new method to become a standard method.
Validation of a test method is the measurement of the performance characteristics of a test method. It is carried out once, by one laboratory. In essence, it is the process of comparing the results of the new method with the results obtained from the standard reference method, and it shows that the method actually works in the laboratory that performs it.
Verification of a method is comparing the performance of a new method, carried out by all the laboratories that use the methods for routine testing (the methods that have been standardized).
For qualitative methods that test for the presence or absence of a microorganism, the concerns are the sensitivity of the test method, the relative level of detection, and the selectivity of the method.
For quantitative methods, the factors of interest are accuracy, precision, the limit of quantification, the lowest level at which organisms can be counted, and finally, no less important, selectivity/specificity.
MicroVal works by inviting a referee laboratory to prepare samples and send them to the participating laboratories (using the standard methods and the method awaiting validation). The results are collected and analyzed by the referee laboratory and reported back to MicroVal.
If the results are correct, the certification body will assess and check whether the results can meet the requirements of ISO 16140, and will certify that the method is valid and gives results equivalent to the reference method.
So, once all the results have been produced according to the standard, they are analyzed statistically in accordance with the standard, ISO 16140-3. In the near future, there will be an Excel spreadsheet on the ISO website that allows simpler calculation of the statistics used in analyzing the results. And once the statistics have been done, they will show whether the method is valid or not.
Source: www.nissui-pharm.co.jp