Guidelines for Laboratories Performing Microbiological and Chemical Analyses of Food, Dietary Supplements, Pharmaceuticals, and Cannabis FAQ

AOAC INTERNATIONAL Guidelines for Laboratories Performing Microbiological and Chemical Analyses of Food, Dietary Supplements, Pharmaceuticals, and Cannabis: An Aid to Interpretation of ISO/IEC 17025:2017, Seventh Edition, 2024

2024 Version Frequently Asked Questions

FAQ 1:

7.5.1 Technical Records: The laboratory shall ensure that technical records for each laboratory activity contain the results, report and sufficient information to facilitate, if possible, identification of factors affecting the measurement result and its associated measurement uncertainty and enable the repetition of the laboratory activity under conditions as close as possible to the original:

d) Column lot number

Question: Does this refer to analytical LC/GC columns or preparation (clean up) columns, such as SPE cartridges?  Some LC columns do not come with a lot number, but a serial number is.  Is that appropriate to meet this requirement?            

Answer: Since analytical columns contribute to the measurement uncertainty of the method, it is necessary to record that information.  In cases where a lot number is not provided a serial number still provides a record of that unique item.  Regarding clean up columns, traceability is still necessary.  This can be helpful in laboratories when a lot of cartridges are underperforming or contaminated.

FAQ 2:

AOAC 7.7.1: Quality control procedures shall be defined for both quantitative and qualitative methods, which include…the use of quality control materials in a matrix that is validated for use within the scope of the test method in order to demonstrate that the test worked properly.

Question: If a lab has 14/15 methods on their scope that are validated for the same matrix, does the 15th method require a different matrix in order to fulfill this requirement, since the 15th method is not validated for the matrix used?

Answer: Selection of a QC matrix needs to be relevant to the regular testing practices in the laboratory.  Not all matrices tested in the laboratory need to be tested, but the QC matrix must represent for the method and the matrices normally run in the laboratory.  For example, if the laboratory runs meat samples and does not run non-fat dry milk (NFDM), then NFDM is not a regular matrix to be used as a QC matrix.