- (Revised) Section 6.4.4. of the Guidelines states that reagents, reagent solutions, sample solutions, and internal reference materials [including certified reference materials (CRMS) used as internal reference materials] shall not be used past their expiration date without recorded verification that they are still suitable for use. Media and CRMS cannot be used beyond their expiration date. Note: Expired CRMs can be qualified as Reference Materials (RMS).
Question: When can an expired CRM be used?
Answer: A CRM is an RM characterized by a metrologically valid procedure for one or more specified properties, accompanied by a reference material certificate that provides: 1) the value of the specified property, 2) its associated uncertainty, and 3) a statement of metrological traceability. When A CRM expires it loses a link to its uncertainty and traceability but still may be sufficiently homogeneous and stable with respect to one or more of its specified properties. Thus, a CRM that has passed its expiration date can still be used as a QC or as an RM if it is used in a manner that does not require the application of these two lost attributes as long as it is evaluated and re-qualified for suitability.
ISO Guide 80:2014
Guidance for the in-house preparation of quality control materials (QCMs)
- Section 8.8.1. of the Guidelines states that internal audits of laboratory information management systems shall be conducted at least once per accreditation cycle.
Question: What information is required to satisfy this requirement?
Answer: The laboratory is required to audit the acquisition, transfer and data storage process in the LIMS, along with permissions for access to the various data to ensure only authorized personnel can access the different parts of the LIMS
3. Question: Appendix A: Equipment in the 2018 AOAC Guidelines and if there can be an acceptable alternative to measuring the mass of water as a means of verifying the accuracy of volumetric delivery devices: mechanical pipets, mechanical burets and liquid dispensers:
Specifically this concerns bottle top dispensers. “We verify our bottle top dispensers by dispensing the liquid needing measured (usually an acid) into a class A cylinder on the day of use. If the volume is accurate, the measurement is documented and the dispenser is then used freely until the volume is changed or until next day of use.
The question is, can this volume check method be considered an acceptable alternative to weighing on a balance as we are not wanting to put water through our acid dispensers?
Answer: An acceptable alternative to weighing the mass of liquid delivered by a bottle top dispenser would be through measuring the dispensed volume of liquid. It is up to the lab to ensure the alternative to weighing is suitable for its intended use.