title: Quantification of urinary 18-hydroxycortisol using LC-MS/MS.
abstract: BACKGROUND
  Urinary 18-hydroxycortisol has been investigated as a marker of aldosterone-producing adenoma (APA). The aim of this study was to develop and validate a method for the measurement of 18-hydroxycortisol using liquid chromatography-tandem mass spectrometry (LC-MS/MS).
  
  
  METHODS
  Urine was collected over a 24-hour period in patients with APA (n = 11), idiopathic hyperaldosteronism (IHA, n = 9), and essential hypertension (EH, n = 6). 18-Hydroxycortisol was extracted in solid-phase, and measured by LC-MS/MS based on selected reaction monitoring.
  
  
  RESULTS
  The method allowed quantification of 18-hydroxycortisol with a lower quantification limit of 0.26 nmol/L, intra- and inter-assay coefficients of variation of <3.4% and a range of analytical recovery of 98.0-103.7%. Urinary 18-hydroxycortisol excretion for APA, IHA and EH were determined as 725 (SD 451), 102 (SD 68) and 88 (SD 76) nmol/day, respectively.
  
  
  CONCLUSIONS
  The proposed method met the basic analytical requirements and was considered to be useful in the screening and differential diagnosis of APA.
authors.affiliation: Faculty of Health Sciences, Hokkaido University, Sapporo, Japan.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Jin
authors.forename: Norio
authors.initials: N
authors.lastname: Wada
authors.forename: Yuji
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Shu-Ping
authors.initials: SP
authors.lastname: Hui
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Sakurai
authors.forename: Hirotoshi
authors.initials: H
authors.lastname: Fuda
authors.forename: Seiji
authors.initials: S
authors.lastname: Takeda
authors.forename: Masato
authors.initials: M
authors.lastname: Fujikawa
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Yanagisawa
authors.forename: Shigeo
authors.initials: S
authors.lastname: Ikegawa
authors.forename: Takao
authors.initials: T
authors.lastname: Kurosawa
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Chiba
mesh_terms: D000236:Adenoma / Q000652:urine*; D000310:Adrenal Gland Neoplasms / Q000652:urine*; D000450:Aldosterone / Q000096:biosynthesis; D014408:Biomarkers, Tumor / Q000652:urine*; D002853:Chromatography, Liquid; D000075222:Essential Hypertension; D006801:Humans; D006854:Hydrocortisone / Q000031:analogs & derivatives* / Q000652:urine; D006929:Hyperaldosteronism / Q000652:urine*; D006973:Hypertension / Q000652:urine*; D057230:Limit of Detection; D015203:Reproducibility of Results; D052617:Solid Phase Microextraction; D053719:Tandem Mass Spectrometry
chemical_list: D014408:Biomarkers, Tumor; D000450:Aldosterone; C033689:18-hydroxycortisol; D006854:Hydrocortisone
keywords: Steroid; aldosteronism; hypertension; mass spectrometry