Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

An international assessment of the metrological equivalence of higher-order measurement services for creatinine in serum



Johanna Camara, Katrice A. Lippa, David L. Duewer, Hugo H. Gasca-Aragon, Blaza Toman


Background: The CCQM-K80 Key Comparison directly assessed the equivalence of many of the world’s higher-order value-assigned materials (HOVAMs) for creatinine in human serum. This 2009 international study compared the certified values and uncertainties of the materials using measurements made under repeatability conditions. Methods: The study evaluated 17 materials submitted by six national metrology institutes (NMIs). The creatinine quantity in these materials ranged from 3 mg/kg to 57 mg/kg (about 0.3 mg/dL to 6 mg/dL or 30 nmol/L to 500 nmol/L). All materials were stored and prepared according the specifications provided by the participating NMIs. Samples were processed and analyzed under repeatability conditions by one analyst using isotope-dilution liquid chromatography-mass spectrometry in two measurement campaigns. The certified values and repeatability measurements were compared using uncertainty-weighted generalized distance regression. Results: The instrumental repeatability relative standard deviation was 1.2 %. The measurement design required assessment of within-unit and between-campaign variability in addition to measurement repeatability. At a 95 % level of confidence, the certified values for all 17 materials agreed to within their assigned uncertainties. Conclusion: CCQM-K80 demonstrated the metrological equivalence of the currently available HOVAMs for creatinine in human serum and of the creatinine measurement services provided by the participating NMIs.
Analytical and Bioanalytical Chemistry


creatinine, reference material, international comparison


Camara, J. , Lippa, K. , Duewer, D. , Gasca-Aragon, H. and Toman, B. (2012), An international assessment of the metrological equivalence of higher-order measurement services for creatinine in serum, Analytical and Bioanalytical Chemistry, [online], (Accessed July 18, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created April 2, 2012, Updated November 10, 2018