title: Ultra high performance liquid chromatography-tandem mass spectrometry vs. commercial immunoassay for determination of vancomycin plasma concentration in children. Possible implications for everyday clinical practice.
abstract: BACKGROUND
  Vancomycin therapeutic drug monitoring (TDM) is necessary for effective and safetherapy. The aim of the this paper was to develop a specific and robust ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for vancomycin quantification starting from low plasma volumes to be applied for the routine TDM in children.
  
  
  METHODS
  Samples from children receiving intravenous vancomycin were analysed using a TSQ Quantum Access MAX Triple Quadrupole system coupled with an Accela 1250 UHPLC system after a rapid protein precipitation. Gradient separation chromatography was carried out using a Hypersil GOLD aQ C18 column (50 × 2.1 mm, particle size 1.9 μm). Method performance was validated following international guidelines.
  
  
  RESULTS
  UHPLC-MS/MS allowed a rapid and specific quantification of vancomycin over the range 0.1-128 μg/mL from 50 μL of plasma with high reproducibility and accuracy in the absence of matrix effect. The comparison with the commercial immunoassay performed on 138 samples demonstrated the presence of a proportional bias. The concentrations of vancomycin measured with immunoassay were found to be 4.5% (95% CI: 1.3-7.7) higher than those determined with UHPLC-MS/MS. Importantly, a clinical discordance was found in about 10% of samples analysed.
  
  
  CONCLUSIONS
  This new UHPLC-MS/MS method is accurate and specific for the measurement of vancomycin starting from small (50 μL) plasma volumes. The use of UHPLC-MS/MS is recommended to prevent a misclassification of therapeutic or toxic vancomycin levels in paediatrics.
authors.affiliation: a Clinical Pathology Laboratory Unit , Istituto Giannina Gaslini , Genoa , Italy.
authors.forename: Sebastiano
authors.initials: S
authors.lastname: Barco
authors.affiliation: b Infectious Disease Unit , Istituto Giannina Gaslini , Genoa , Italy.
authors.forename: Elio
authors.initials: E
authors.lastname: Castagnola
authors.affiliation: a Clinical Pathology Laboratory Unit , Istituto Giannina Gaslini , Genoa , Italy.
authors.forename: Iulian
authors.initials: I
authors.lastname: Gennai
authors.affiliation: a Clinical Pathology Laboratory Unit , Istituto Giannina Gaslini , Genoa , Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Barbagallo
authors.affiliation: b Infectious Disease Unit , Istituto Giannina Gaslini , Genoa , Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Loy
authors.affiliation: a Clinical Pathology Laboratory Unit , Istituto Giannina Gaslini , Genoa , Italy.
authors.forename: Gino
authors.initials: G
authors.lastname: Tripodi
authors.affiliation: a Clinical Pathology Laboratory Unit , Istituto Giannina Gaslini , Genoa , Italy.
authors.forename: Giuliana
authors.initials: G
authors.lastname: Cangemi
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D016903:Drug Monitoring / Q000379:methods*; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D007223:Infant; D008297:Male; D015203:Reproducibility of Results; D053719:Tandem Mass Spectrometry / Q000379:methods*; D014640:Vancomycin / Q000097:blood*; D055815:Young Adult
chemical_list: D014640:Vancomycin
keywords: Method validation; Therapeutic drug monitoring; UHPLC–MS/MS; Vancomycin