title: Rifampicin Interference in the Measurement of Urinary Catecholamines by High-Performance Liquid Chromatography.
abstract: Measurement of urine and plasma catecholamines and their metabolites are essential for the diagnosis of pheochromocytoma. Here, we report our experience of rifampicin interference in the measurement of urinary catecholamines using high-performance liquid chromatography. During a 1-year period, four patients taking rifampicin showed unusual chromatograms with markedly larger norepinephrine spikes, translating to highly elevated norepinephrine concentrations: 290.2, 720.1, 312.0, and 812.7 μg/L. This interference effect did not occur when samples were prepared using the alumina method, with norepinephrine values decreasing to 26.4, 31.5, 21.9, and 17.2 μg/L. Interference was also absent in data using LC-MS/MS. Clinical laboratories should verify whether rifampicin interferes with test results in their assays, and physicians should be informed that urinary norepinephrine levels can be falsely elevated in patients taking rifampicin.
authors.affiliation: Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.
authors.forename: Hyun-Ki
authors.initials: HK
authors.lastname: Kim
authors.affiliation: Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.
authors.forename: Dae-Hyun
authors.initials: DH
authors.lastname: Ko
authors.affiliation: Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.
authors.forename: Tae-Dong
authors.initials: TD
authors.lastname: Jeong
authors.affiliation: Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.
authors.forename: Sang-Hee
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.
authors.forename: Woochang
authors.initials: W
authors.lastname: Lee
authors.affiliation: Department of Laboratory Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Soo-Youn
authors.initials: SY
authors.lastname: Lee
authors.affiliation: Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea sailchun@amc.seoul.kr.
authors.forename: Sail
authors.initials: S
authors.lastname: Chun
authors.affiliation: Department of Laboratory Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Junghan
authors.initials: J
authors.lastname: Song
authors.affiliation: Department of Laboratory Medicine, University of Ulsan College of Medicine and Asan Medical Center, Seoul, Korea.
authors.forename: Won-Ki
authors.initials: WK
authors.lastname: Min
mesh_terms: D002395:Catecholamines / Q000652:urine*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D012293:Rifampin / Q000494:pharmacology*
chemical_list: D002395:Catecholamines; D012293:Rifampin
keywords: catecholamine; high-performance liquid chromatography; interference; rifampicin