The competitive Normetanephrine & Metanephrine (Plasma) ELISA Kit uses the microtiter plate format. Metanephrine and normetanephrine, respectively, are bound to the solid phase of the microtiter plate. Acylated nor-/metanephrines from the sample and solid phase bound nor-/metanephrines compete for a fixed number of antiserum binding sites. When the system is in equilibrium, free Antigens and free Antigens-antiserum complexes are removed by washing. The antibody bound to the solid phase nor-/metanephrine is detected by anti-rabbit IgG / peroxidase. The substrate TMB / peroxidase reaction is monitored at 450 nm. The amount of antibody bound to the solid phase catecholamine is inversely proportional to the catecholamine concentration of the sample. Sample Types: EDTA plasma. Range: Metanephrine: 20 - 3000 pg/ml, Normetanephrine: 20 - 3000 pg/ml. Sensitivity: Metanephrine: 10 pg/ml, Normetanephrine: 15 pg/ml. Time: Overnight ? Normetanephrine and metanephrine are physiologically formed from the catechol-amines noradrenaline and adrenaline by the enzyme catechol-O-methyltransferase (COMT). Increased levels of normetanephrine and metanephrine can be found in pheochromocytoma, ganglioneuroma and other neurogenic tumors. The Normetanephrine & Metanephrine (Plasma) ELISA assay kit provides materials for the quantitative measurement of free normetanephrine and metanephrine in EDTA plasma. Normetanephrine and metanephrine are quantitatively acylated to their N-acyl-derivates.