Evaluation of specific high-performance liquid-chromatographic determinations of urinary metanephrine and normetanephrine by comparison with isotope dilution mass spectrometry
| Autor: | J. J Willemsen, H A. Ross, B.G. Wolthers, Ido P. Kema, C.G.J. Sweep |
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| Rok vydání: | 2001 |
| Předmět: |
Adult
Male Dopamine Clinical Biochemistry Adrenal Gland Neoplasms Urine Pheochromocytoma Isotope dilution Mass spectrometry Normetanephrine High-performance liquid chromatography Sensitivity and Specificity Gas Chromatography-Mass Spectrometry Excretion chemistry.chemical_compound Reference Values Electrochemistry Humans Chromatography High Pressure Liquid Metanephrine Aged Creatinine Sex Characteristics Chromatography Chemistry General Medicine Metanephrines Middle Aged Female |
| Zdroj: | Annals of clinical biochemistry. 38(Pt 6) |
| ISSN: | 0004-5632 |
| Popis: | A method for the determination of metanephrine (MN; also known as metadrenaline), normetanephrine (NMN; also known as normetadrenaline) 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 MN, NMN and 3-MT, respectively, in a group of healthy controls consisting of 30 women and 30 men. A systematic difference was 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 metanephrines in the diagnosis of phaeochromocytoma. At lower concentrations (MN, 248 nmol/L; NMN, 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 MN and NMN excretion when expressed in nmol per 24 h and nmol/mmol creatinine, respectively, by both ECD and GC-MS methods. |
| Databáze: | OpenAIRE |
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