Plasma symmetric dimethylarginine reference limits from the Framingham offspring cohort.

BACKGROUND Symmetric dimethylarginine (SDMA) is a by-product of protein methylation. Once released from proteins, SDMA is eliminated by the kidneys; consequently, plasma concentration has been suggested as a sensitive marker of renal function. Furthermore, recent work implicates SDMA in the pathogenesis of cardiovascular disease. To date, reference limits for SDMA plasma concentrations in healthy individuals are lacking.