Reference values for serum nitric oxide metabolites in an adult population

Abstract

Objectives: To determine reference values for serum nitric oxide metabolites (nitrite+nitrate=NO(x)) concentrations in adult subjects.

Design and methods: Serum NO(x) concentration was measured, using the Griess method, in 694 non-smoking apparently healthy subjects, randomly selected from a population-based study. The International Federation of Clinical Chemistry guidelines and the robust method were used for determining reference values.

Results: The 95% reference values for serum NO(x) concentration and serum NO(x)/creatinine ratio were 11.5 to 76.4 micromol/L and 0.111 to 0.729 in men and 10.1 to 65.6 micromol/L and 0.121 to 0.777 in women, respectively. With increasing body mass index, upper limits of serum NO(x) and the NO(x)/creatinine ratio increased in women and decreased in men. Serum NO(x) levels above upper limits predicted both diabetes and metabolic syndrome in women.

Conclusions: This study reports the first set of reference values for serum NO(x) concentration and NO(x)/creatinine ratio in a relatively large healthy non-smoking population.