Calibration of Fractionated Metanephrines in Urine: Still an Issue?

摘要: Measurement of fractionated total metanephrines in urine provides important information for the diagnosis pheochromocytoma(1). Reference intervals that distinguish patients who harbor a pheochromocytoma from those with similar symptoms not actually caused by this disease are highly variable(2)(3)(4). Such differences may be variations analytical methods, selection negative controls establishing reference values, age, and sex(4). A group 3 laboratories have reported journal significantly higher results than expected urinary during successive proficiency surveys 2003 2004. These were due to assigned values Bio-Rad Laboratories calibrator 24%–33% lower actual concentration(5). To determine whether concentration has been corrected, we examined proficiency-test data obtained ProBioQual, French quality-assurance center, assess accuracy metanephrine collected 48 2004–2006 period. We included only 8 target concentrations between 1000 1800 nmol/L retrospective analysis exclude uncertainty produced measurements very low …