title: Detection of synthetic glucocorticoids by liquid chromatography-tandem mass spectrometry in patients being investigated for Cushing's syndrome.
abstract: BACKGROUND
  We report a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the detection of four commonly prescribed steroid drugs (prednisolone, dexamethasone, betamethasone and beclomethasone dipropionate) while simultaneously measuring 24-h urine free cortisol and cortisone in patients.
  
  
  METHODS
  Two hundred and fifty microlitre aliquots of urine were spiked with internal standard and extracted with dichloromethane. The MS instrument was operated with positive electrospray and multiple reaction monitoring. Two transitions were monitored for each analyte of interest and the ratio of the intensities of the product ion fragments was established.
  
  
  RESULTS
  The LC-MS/MS method for the measurement of urine free cortisol and cortisone was established. The assay was linear up to 788 nmol/L for cortisol and 777 nmol/L for cortisone, with a limit of quantitation of 5.0 nmol/L for both. Analysis time per sample was seven minutes. Transitions for four synthetic glucocorticoids were included, and they were identified based on the ratio of the intensities of product ion fragments. Analysis of 219 samples collected from 154 patients (55 male and 99 female) revealed the presence of prednisolone in five samples from three patients. Dexamethasone was detected in samples from four patients, and betamethasone was detected in one sample.
  
  
  CONCLUSIONS
  This is the first LC-MS/MS method in routine use to combine quantification of urinary cortisol and cortisone and detection of synthetic glucocorticoids in patients being investigated for Cushing's syndrome. Since the most common quoted cause of Cushing's syndrome is steroid treatment, this is a valuable diagnostic tool.
authors.affiliation: Department of Clinical Biochemistry, Northwick Park Hospital, North West London Hospitals NHS Trust, Harrow, Middlesex HA1 3UJ,  UK.
authors.forename: N K
authors.initials: NK
authors.lastname: Djedovic
authors.forename: S J
authors.initials: SJ
authors.lastname: Rainbow
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001507:Beclomethasone / Q000627:therapeutic use / Q000652:urine; D001623:Betamethasone / Q000627:therapeutic use / Q000652:urine; D002648:Child; D002853:Chromatography, Liquid / Q000592:standards*; D003348:Cortisone / Q000652:urine; D003480:Cushing Syndrome / Q000175:diagnosis* / Q000188:drug therapy; D003907:Dexamethasone / Q000627:therapeutic use / Q000652:urine; D005260:Female; D005938:Glucocorticoids / Q000627:therapeutic use / Q000652:urine*; D006801:Humans; D006854:Hydrocortisone / Q000652:urine; D057230:Limit of Detection; D008297:Male; D008875:Middle Aged; D011239:Prednisolone / Q000627:therapeutic use / Q000652:urine; D012015:Reference Standards; D053719:Tandem Mass Spectrometry / Q000592:standards*; D055815:Young Adult
chemical_list: D005938:Glucocorticoids; D003907:Dexamethasone; D001623:Betamethasone; D011239:Prednisolone; D001507:Beclomethasone; D003348:Cortisone; D006854:Hydrocortisone