Reagents and culture media
All reagents and culture media should be recorded upon receipt or preparation. Some manufacturers record the relevant information in registers, others record the information in computer systems.
Written standard operating procedures should be followed for the preparation of reagents, when these are not purchased from suppliers. All reagents and volumetric solutions should be appropriately labelled. Ensure that the labels indicate at least the concentration, the standardization factor, the shelf-life, the due date for re-standardization and the storage conditions of the reagent. It is also necessary to check whether the analyst that prepared the reagent had signed and dated the label. You can use this information to verify who prepared the reagent, and whether the SOP was followed by verifying the calculations in the analyst log book.
Manufacturers have to ensure that the culture media they will use is suitable for the intended use. However, false results indicating micro contamination, are also not desired. Verify whether the manufacturer applies both positive and negative controls on culture media.
The size of the inoculum used in positive controls should be appropriate to the sensitivity required.