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Standards

Reference materials

Photograph of a unit of SRM 2262 consisting of a labeled box and a labeled amber vial.

Purchase SRMs

photo of NIST SRM 2385, spinach, on background of spinach leaves

Learn more about SRMs

From cholesterol to cement, peanut butter to paint, reference materials enable laboratories to accurately measure and understand all sorts of substances, helping to ensure that our food is safe, our buildings are sturdy, and our blood test results are correct.

NIST offers three different types of reference materials: Standard Reference Materials (SRMs), Reference Materials and Research Grade Test Materials (RGTMs). The chart below explains the differences between the three.

Standard Reference Material (SRM)	Reference Material	Research Grade Test Material (RGTM)
“Our best assertion of truth”; material is thoroughly measured and characterized; values of material’s properties along with uncertainties in the measurements are “certified” (backed by a certificate of analysis).	Not our best assertion of truth, but the best measurement we can make, along with our best estimate of the uncertainty of the measurement; non-certified values for measurements and uncertainties.	“Good enough for intended purpose.” Typically doesn’t contain a measurement value; designed for distribution so that multiple labs can make measurements and compare their results.
The material’s values and properties are traceable (linked directly) to a higher order reference system, typically the International System of Units (SI).	May be traceable to a standard method (such as mass spectroscopy); values may not be used for traceability.	Not traceable to the SI.
Comes with certificate of analysis (COA) that states the value of the certified properties.	Comes with a Reference Material Information Sheet (RMIS) that details the noncertified values of the material and related uncertainties.	Typically comes with an information sheet describing its intended use in an interlaboratory intercomparison exercise.
Sold by NIST and its authorized distributors.	Sold by NIST or other suppliers.	Distributed to other labs by NIST, which make measurements of the material.
Example: Infant formula	Examples: NIST monoclonal antibody standard, hemp	Examples: NISTCHO (living cells that produce monoclonal antibodies), Mpox, H5N1 (bird flu)
Used for international trade harmonization, critical measurements, calibrating instruments, validating methods.	Used for analytical measurements, quality assurance, development of methods or materials when SRM isn’t available.	Used for early-stage research, interlaboratory comparisons and to determine whether or not an RM is needed.