title: Convenient chromatographic prepurification step before measurement of urinary cortisol by radioimmunoassay.
abstract: We applied various prepurification protocols (extraction with different solvents, liquid/solid separation on bonded silica media, Celite, and Sephadex LH20 chromatography) with a range of commercially available RIA kits to measure cortisol in urine samples. We then compared the results with the concentrations measured by a HPLC method validated with reference to isotope dilution gas chromatography-mass spectrometry. We conclude that chromatography on a commercial, prepacked diol minicolumn (Waters Sep-Pak Vac RC) in combination with dichloromethane extraction is a convenient and very effective purification step before RIA of urinary cortisol in patients not receiving corticoid medication. We tested numerous steroids for interference and found that free polar cortisol derivatives (hydroxylated or hydrogenated) could only partially account for the overestimations routinely encountered when free urinary cortisol concentrations are measured by direct RIA.
authors.affiliation: Laboratoire de Biologie Hormonale, Hôpital Saint-Louis, Paris, France.
authors.forename: G
authors.initials: G
authors.lastname: Morineau
authors.forename: J
authors.initials: J
authors.lastname: Gosling
authors.forename: M C
authors.initials: MC
authors.lastname: Patricot
authors.forename: H
authors.initials: H
authors.lastname: Soliman
authors.forename: P
authors.initials: P
authors.lastname: Boudou
authors.forename: A
authors.initials: A
authors.lastname: al Halnak
authors.forename: G
authors.initials: G
authors.lastname: Le Brun
authors.forename: J L
authors.initials: JL
authors.lastname: Brérault
authors.forename: R
authors.initials: R
authors.lastname: Julien
authors.forename: J M
authors.initials: JM
authors.lastname: Villette
authors.forename: J
authors.initials: J
authors.lastname: Fiet
mesh_terms: D000328:Adult; D002845:Chromatography / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D007692:Diatomaceous Earth; D005189:False Positive Reactions; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D006854:Hydrocortisone / Q000652:urine*; D008297:Male; D011786:Quality Control; D011863:Radioimmunoassay / Q000706:statistics & numerical data; D012016:Reference Values; D012680:Sensitivity and Specificity; D012727:Sex Characteristics; D013256:Steroids / Q000652:urine
chemical_list: D013256:Steroids; D007692:Diatomaceous Earth; D006854:Hydrocortisone