01Compare the jobs the materials must perform

A reagent may provide the molecule used to investigate a biological question. A reference material may support calibration, method assessment or another defined measurement task. The evidence needed for those roles can differ.

NIST defines a certified reference material through characterisation of specified properties using a metrologically valid procedure, accompanied by certified values, uncertainty and traceability information.NIST — Reference material and certified reference material definitions (opens in a new tab)

The phrase “specified properties” is essential. Certification of one property does not mean that every statement about the material has certified status.

A higher purchase price, an analytical logo or a detailed-looking certificate does not answer these questions by itself.

02Read the status of each reported value

NIST distinguishes its Standard Reference Materials, which provide at least one certified property value, from other reference materials. It also notes that an SRM may include non-certified information in its documentation.NIST — Reference material and certified reference material definitions (opens in a new tab)

For a reader, this means the heading on the document is only the beginning. Locate the specific property and the status assigned to its value. Do not transfer a certified label from one row to all the others.

Imagine a document with a certified concentration and a separately listed identity observation. The observation may be useful, but its evidence and status should be read on their own terms. This hypothetical example does not describe a particular supplier’s certificate.

03A peptide reference can carry non-certified values

NIST’s archived RM 8327 report describes three synthetic peptides intended for evaluating molecular-mass and purity measurements. It explicitly describes its reference values as non-certified and explains that their uncertainties may not cover every source of uncertainty.NIST — Archived RM 8327 report of investigation (opens in a new tab)

The report separately presents area-percent purity, peptide mass purity and molecular-mass information. These are distinct measurands, even though they occur in the same document.NIST — Archived RM 8327 report of investigation (opens in a new tab)

This historical report illustrates why “reference material” and “certified reference material” should not be used interchangeably. The archived document’s stated validity ended in September 2015; it is used here as a reading example, not a current procurement recommendation.NIST — Archived RM 8327 report of investigation (opens in a new tab)

A non-certified value is not automatically useless. Its suitability depends on the decision being made and the limitations stated by its producer.

04Select against the uncertainty the study can tolerate

Write down the property your measurement needs and the acceptable uncertainty before comparing materials. Then check whether the candidate reference’s documentation supports that specific use.

If a reagent lacks the required amount assignment, its chromatographic purity alone cannot fill the gap. Conversely, a reference chosen for a calibrated amount may still need separate evidence for another experimental requirement.

Keep the selection record short and explicit: role, property, supporting document, validity and unresolved limitations. This makes the decision understandable without turning CRM status into a general product-quality ranking or implying that an ordinary research reagent has certified reference status.