title: Vancomycin assay performance in patients with acute renal failure.
abstract: OBJECTIVE
  Fluorescence polarization immunoassays (FPIA) have been reported to overestimate vancomycin serum concentrations compared to high-performance liquid chromatography (HPLC) or enzyme multiplied immunoassay technique (EMIT) in patients with chronic renal disease. The assay manufacturer has modified the FPIA to remedy this overestimation. The purpose of this study was to compare the assay performance of two FPIAs to EMIT in acute renal failure patients receiving vancomycin and continuous venovenous hemofiltration.
  
  
  METHODS
  Open-label trial.
  
  
  METHODS
  Intensive care unit in a university affiliated hospital.
  
  
  METHODS
  15 serum and ultrafiltrate samples were obtained from 14 critically ill patients (mean +/- SD; 57 +/- 12 years; 8 males/6 females).
  
  
  RESULTS
  Vancomycin concentrations were determined by a polyclonal FPIA (pFPIA) performed on the TDx system, a monoclonal FPIA (mFPIA) performed on the AxSYM system and EMIT. The coefficient of variation for all assays was < 5%. The mean difference +/- SDd between mFPIA vs EMIT and pFPIA vs EMIT assays in serum were: -0.08 +/- 1.55 and 1.24 +/- 2.11 mg/l, respectively. The limits of agreement between the mFPIA vs EMIT and pFPIA vs EMIT assays in serum were: -3.18 to 3.03 and -2.99 to 5.46 mg/l, respectively.
  
  
  CONCLUSIONS
  Our data demonstrate that the manufacturer's changes to the pFPIA have reduced overestimation. The mFPIA appears to be an acceptable assay for measuring vancomycin serum concentrations in acute renal failure patients and does not significantly overestimate these concentrations.
authors.affiliation: Department of Pharmacy, Clarian Health Partners, Inc., Indianapolis, Indiana, USA.
authors.forename: T N
authors.initials: TN
authors.lastname: Trujillo
authors.forename: K M
authors.initials: KM
authors.lastname: Sowinski
authors.forename: R A
authors.initials: RA
authors.lastname: Venezia
authors.forename: M K
authors.initials: MK
authors.lastname: Scott
authors.forename: B A
authors.initials: BA
authors.lastname: Mueller
mesh_terms: D058186:Acute Kidney Injury / Q000097:blood* / Q000188:drug therapy; D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000097:blood / Q000493:pharmacokinetics*; D002851:Chromatography, High Pressure Liquid; D017248:Enzyme Multiplied Immunoassay Technique; D005260:Female; D016231:Fluorescence Polarization Immunoassay / Q000592:standards; D006440:Hemofiltration / Q000592:standards*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D014640:Vancomycin / Q000097:blood / Q000493:pharmacokinetics*
chemical_list: D000900:Anti-Bacterial Agents; D014640:Vancomycin