Reference Standard vs Reference Material

The terms overlap because they come from different communities. Metrology uses reference material (RM) and certified reference material (CRM), defined in the VIM and produced under ISO 17034. Pharmaceutical regulation uses reference standard: ICH Q7 describes primary reference standards, obtained from an officially recognised source or shown to be authentic through extensive analytical testing, and secondary (working) reference standards, which are qualified against a primary standard and used routinely. Pharmacopeias such as USP issue official reference standards for use with their monographs.

Analytical standard is mostly a catalogue term. A product sold as an analytical standard may be a CRM with a full certificate, an RM with characterisation data, or a high-purity chemical with a lot CoA. The label alone does not tell a lab which it is.

Choosing which to use depends on the job. A pharmacopeial assay generally calls for the official reference standard named in the monograph. A calibration that needs a stated uncertainty and traceability calls for a CRM. A system-suitability check or trend control may only need a well-characterised in-house or commercial material with documented qualification.

Records that support the choice: the certificate or CoA for the lot in use, storage conditions and expiry or retest date, qualification data for any secondary standard against its primary, and a usage log linking the standard lot to the analyses that relied on it. Under 21 CFR 211.194(c), records of reference standards prepared by a drug manufacturer must be kept.

Related concepts: certified reference material, reference standard qualification and CoA. Sources: ICH Q7, 21 CFR 211.194, ISO 17034:2016, JCGM 200 (VIM).