A unit of SRM 956e consists of six sealed borosilicate glass ampoules of frozen human serum, two ampoules each of three different concentration levels: Level 1, Level 2, and Level 3. Each ampoule contains approximately 2 mL of frozen human serum. The certified values delivered by this Standard Reference Material (SRM) are intended for the calibration and validation of procedures and methods employed in clinical analysis for the determination of electrolytes in either diluted or undiluted human serum or plasma. SRM 956e_cert SRM 956e _SDS

The electrolytes in frozen human serum are primarily intended for use in the calibration and validation of procedures and methods employed in clinical analysis for the determination of electrolytes in either diluted or undiluted human serum or plasma. This SRM can be used for calibrating direct-reading ion-selective electrode (ISE) analyzers and for quality assurance in validating secondary reference materials.

Certified for the analytes listed below. Calcium (Ca), Chloride (Cl), Lithium (Li), Magnesium (Mg), Potassium (K), Sodium (Na)

Reference/Informational value is provided for the following analytes. Ionized Calcium (Ca²⁺, 12 H₂O), Phosphate (PO₄^3-), Phosphorus (P)

See certificate for values and more details at nist.gov/SRM.

NIST is a registered trademark of National Institute of Standards and Technology

SRM is a registered trademark of National Institute of Standards and Technology