title: Quantitation of Free Metanephrines in Plasma by Liquid Chromatography-Tandem Mass Spectrometry.
abstract: Plasma metanephrines are measured to aid in the diagnosis of pheochromocytomas. In patients with pheochromocytomas there is excessive production of catecholamines and metanephrines. Measurement of plasma free metanephrines is one of the first-line clinical tests that are used for the diagnosis and follow-up of pheochromocytoma. We describe here a liquid chromatography-tandem mass spectrometry method to measure free metanephrines in plasma. Free metanephrine and normetanephrine are extracted via solid-phase extraction. After extraction and evaporation, the reconstituted supernatant is analyzed by high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The MS/MS is set to selective reaction monitoring mode (180.1 → 148.1 m/z for metanephrine, 183.1 → 168.1 for d3-metanephrine, 166.1 → 134.1 m/z for normetanephrine, and 169.1 → 137.2 m/z for d3-normetanephrine) with positive electrospray ionization. Quantitation is based on peak area ratio of the analyte to its respective deuterated internal standard. The assay is linear from 5.9 to 4090.0 pg/mL for metanephrine and 22.0 to 4386.7 pg/mL for normetanephrine with precision of <6 % over the ranges.
authors.affiliation: Department of Clinical Pathology, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH, 44195, USA.
authors.forename: Courtney
authors.initials: C
authors.lastname: Heideloff
authors.affiliation: Department of Clinical Pathology, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH, 44195, USA.
authors.forename: Drew
authors.initials: D
authors.lastname: Payto
authors.affiliation: Department of Laboratory Medicine, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH, 44195, USA. wangs2@ccf.org.
authors.forename: Sihe
authors.initials: S
authors.lastname: Wang
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000097:blood; D001774:Blood Chemical Analysis / Q000379:methods*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D008676:Metanephrine / Q000097:blood*; D010673:Pheochromocytoma / Q000097:blood; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D008676:Metanephrine
keywords: Liquid chromatography; Mass spectrometry; Metanephrine; Normetanephrine; Pheochromocytoma; Plasma; Quantification