Performance of plasma free metanephrines measured by liquid chromatography-tandem mass spectrometry in the diagnosis of pheochromocytoma

作者：Peaston Robert T^*; Graham Kendon S; Chambers Erin; van der Molen Jan C; Ball Stephen

来源：Clinica Chimica Acta, 2010, 411(7-8): 546-552.

DOI：10.1016/j.cca.2010.01.012

• Pheochromocytoma
• Plasma metanephrines
• LC-MS/MS
• Enzyme immunoassay

Background: Plasma free metanephrines have proved a highly sensitive biochemical test for the diagnosis or pheochromocytoma. We have developed and validated a simple, LC-MS/MS method to determine plasma metanephrines and compared the diagnostic efficacy of the method with an enzyme immunoassay procedure in 151 patients, 38 with histologically confirmed pheochromocytoma.
Methods: Off-line solid phase extraction in a 96-well plate format was used to isolate metanephrines from 100-mu L. of plasma, followed by rapid separation with hydrophilic interaction chromatography. Mass spectrometry detection was performed in multiple-reaction monitoring mode using a tandem quadrupole mass spectrometer with positive electrospray ionization.
Results: Detection limits were <0.1 nmol/l with method linearity up to 23.0 nmol/L for normetanephrine (NMN), metanephrine (MN) and 3-methoxytyramine (3-MT). Method comparison with an automated LC-MS/MS yielded Deming regression slopes of r=0.94 for NMN, r=0.98 for MN and r=0.94 for 3-MT. Method comparison with enzyme immunoassay revealed regression slope of r=1.28 (NMN) and 1.25 (MN) with values approximately 25% lower than LC-MS/MS. Plasma metanephrines by LC-MS/MS identified all 38 patients with phaeochromocytoma compared with 36 cases by immunoassay.
Conclusions: Plasma metanephrines measured by LC-MS/MS are a reliable and sensitive test for the biochemical detection of pheochromocytoma.

• 出版日期2010-4-2