Evaluation of specific high-performance liquid-chromatographic determinations of urinary adrenaline and noradrenaline by comparison with isotope dilution mass spectrometry

A method for the determination of metadrenaline (MA). normetadrenaline (NMA) and 3-methoxytyramine (3-MT) in human urine using high-performance liquid chromatography followed by electrochemical detection (ECD) was validated primarily by comparing the results with those obtained by a gas chromatography mass spectrometry (GC MS) reference method. Correlation coefficients of 0.93, 0.94 and 0.91 were obtained for MA, NMA and 3-MT. respectively, in a group of healthy controls consisting of 30 women and 30 men. A systematic difference wits detected only for 3-MT (-16%). Further tests Of accuracy (linearity and recovery) and precision demonstrated that the described method must be considered to be a reliable approach to assess urinary metadrenalities in the diagnosis of phaeochromocytoma. At lower concentrations (MA, 248 nmol L; NMA. 434 nmol, L; 3-MT, 402 nmol/L), within-assay coefficients of variation were close to 5%, or less (5(.)3, 4(.)6 and 2(.)2%, respectively) and between-assay, Coefficients Of Variation were 8(.)9. 11(.)2 and 12(.)3%, respectively, for the same low levels. This raises the possibility that this method can also be applied to assess urinary free, unconjugated metanephrines. Sex differences were detected for MA and NMA excretion Mien expressed in nmol per 24h and nmol/mmol creatinine, respectively, by both ECD and GC MS methods.