title: A simple, rapid atmospheric pressure chemical ionization liquid chromatography tandem mass spectrometry method for the determination of 25-hydroxyvitamin D2 and D3.
abstract: Vitamin D plays a vital role not only in bone health but also in pathophysiology of many other body functions. In recent years, there has been significant increase in testing of 25-hydroxyvitamin D (25-OH vitamin D), a marker of vitamin D deficiency. The most commonly used methods for the measurement of 25-OH vitamin D are immunoassays and liquid chromatography tandem mass spectrometry (LC-MS-MS). Since immunoassays suffer from inaccuracies and interferences, LC-MS-MS is a preferred method. In LC-MS-MS methods, 25-OH vitamin D is extracted from serum or plasma by solid-phase or liquid-phase extraction. Because these extraction methods are time consuming, we developed an easy method that uses simple protein precipitation followed by injection of the supernatant to LC-MS-MS. Several mass-to-charge (m/z) ratio transitions, including commonly used transitions based on water loss, were evaluated and several tube types were tested. The optimal transitions for 25-OH vitamin D2 and D3 were 395.5 > 269.5 and 383.4 > 257.3, respectively. The reportable range of the method was 1-100 ng/mL, and repeatability (within-run) and within-laboratory imprecision were <4% and <6%, respectively. The method agreed well with the solid-phase extraction methods.
authors.affiliation: Department of Pathology and Laboratory Medicine, Children's Mercy Hospitals and Clinics, Kansas City, MO 64108, USA. ugarg@cmh.edu
authors.forename: Uttam
authors.initials: U
authors.lastname: Garg
authors.forename: Ada
authors.initials: A
authors.lastname: Munar
authors.forename: Clinton
authors.initials: C
authors.lastname: Frazee
authors.forename: David
authors.initials: D
authors.lastname: Scott
mesh_terms: D015652:25-Hydroxyvitamin D 2 / Q000097:blood* / Q000737:chemistry; D001800:Blood Specimen Collection; D002112:Calcifediol / Q000097:blood* / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D016014:Linear Models; D015203:Reproducibility of Results; D059629:Signal-To-Noise Ratio; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D015652:25-Hydroxyvitamin D 2; D002112:Calcifediol