title: Hyaluronic Acid Assays: Turbidimetric or Enzyme-Based Immune Assay? A Method Comparison Study.
abstract: BACKGROUND
  Hyaluronic acid (HA) is proposed as a marker of functional liver capacity. The aim of the present study was to compare a new turbidimetric assay for measuring HA with the current standard method.
  
  
  METHODS
  HA was measured by a particle-enhanced turbidimetric immunoassay (PETIA) and enzyme-linked immunosorbent assay (ELISA) in a 40-sample dilution series and 39 intensive care unit (ICU) patients. Agreement was assessed with Bland-Altman's method.
  
  
  RESULTS
  In the ICU patients, the median HA concentration was 159.0 ng/ml (interquartile range (IQR) 117.5-362.5 ng/ml) with ELISA and 157.5 ng/ml (IQR 92.5-359.6 ng/ml) with PETIA. The mean difference was 12.88 ng/ml (95% CI, -4.3 to 30.1 ng/ml, P = 0.14) and the 95% limits of agreement were -91.17 to 116.9 ng/ml. In the dilution series, the mean difference was -59.26 ng/ml (95% CI, -74.68 to 43.84 ng/ml, P < 0.0001) and the 95% limits of agreement were 35.23 to -153.8 ng/ml.
  
  
  CONCLUSIONS
  We found random variation between the PETIA and ELISA test that could affect performance in a clinical context, but only to a lesser extent in a research context. The new clinical biochemistry assay for HA determination will allow for large studies of the clinical utility of HA.
authors.affiliation: Department of Anesthesiology, Nordsjaellands Hospital, University of Copenhagen, Copenhagen, Denmark. Theis.skovsgaard.itenov@regionh.dk.
authors.forename: Theis S
authors.initials: TS
authors.lastname: Itenov
authors.affiliation: Department of Medical Microbiology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
authors.forename: Nikolai S
authors.initials: NS
authors.lastname: Kirkby
authors.affiliation: Department of Anesthesiology, Nordsjaellands Hospital, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Morten H
authors.initials: MH
authors.lastname: Bestle
authors.affiliation: Department of Clinical Immunology, Odense University Hospital, Denmark.
authors.forename: Anna C
authors.initials: AC
authors.lastname: Nilsson
authors.affiliation: Department of Clinical Biochemistry, Viborg Regional Hospital, Viborg, Denmark.
authors.forename: Erland J
authors.initials: EJ
authors.lastname: Erlandsen
authors.affiliation: Department of Infectious Diseases and Rheumatology, Rigshospitalet, University of Copenhagen, CHIP, Finsencentret, Copenhagen, Denmark.
authors.forename: Lars
authors.initials: L
authors.lastname: Peters
authors.affiliation: Department of Infectious Diseases and Rheumatology, Rigshospitalet, University of Copenhagen, CHIP, Finsencentret, Copenhagen, Denmark.|Department of Clinical Microbiology, Hvidovre Hospital, Hvidovre, Denmark.
authors.forename: Jens-Ulrik
authors.initials: JU
authors.lastname: Jensen
mesh_terms: D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D006820:Hyaluronic Acid / Q000032:analysis* / Q000097:blood; D007362:Intensive Care Units; D008297:Male; D009391:Nephelometry and Turbidimetry / Q000379:methods; D018709:Statistics, Nonparametric
chemical_list: D006820:Hyaluronic Acid
keywords: ELISA; PETIA; biomarker; critical illness; liver failure; validation