title: Reproducibility of serum IgE, Ara h2 skin prick testing and fraction of exhaled nitric oxide for predicting clinical peanut allergy in children.
abstract: BACKGROUND
  Ara h2 sIgE serum levels improve the diagnostic accuracy for predicting peanut allergy, but the use of Ara h2 purified protein as a skin prick test (SPT), has not been substantially evaluated. The fraction of exhaled nitric oxide (FeNO) shows promise as a novel biomarker of peanut allergy. Reproducibility of these measures has not been determined. The aim was to assess the accuracy and reproducibility (over a time-period of at least 12 months) of SPT to Ara h2 in comparison with four predictors of clinical peanut allergy (Peanut SPT, Ara h2 specific Immunoglobulin E (sIgE), Peanut sIgE and FeNO).
  
  
  METHODS
  Twenty-seven children were recruited in a follow-up of a prospective cohort of fifty-six children at least 12 months after an open-labelled peanut food challenge. Their repeat assessment involved a questionnaire, SPT to peanut and Ara h2 purified protein, FeNO and sIgE to peanut and Ara h2 measurements.
  
  
  RESULTS
  Ara h2 SPT was no worse in accuracy when compared with peanut SPT, FeNO, Ara h2 sIgE and peanut sIgE (AUC 0.908 compared with 0.887, 0.889, 0.935 and 0.804 respectively) for predicting allergic reaction at previous food challenge. SPT for peanut and Ara h2 demonstrated limited reproducibility (ICC = 0.51 and 0.44); while FeNO demonstrated good reproducibility (ICC = 0.73) and sIgE for peanut and Ara h2 were highly reproducible (ICC = 0.81 and 0.85).
  
  
  CONCLUSIONS
  In this population, Ara h2 SPT was no worse in accuracy when compared with current testing for the evaluation of clinical peanut allergy, but had-like peanut SPT-poor reproducibility. FeNO, peanut sIgE and Ara h2 sIgE were consistently reproducible despite an interval of at least 12 months between the repeated measurements.
authors: Experimental & Translational Respiratory Medicine Group, Hunter Medical Research Institute, University of Newcastle, Lookout Road, New Lambton, Newcastle, NSW 2305 Australia ; Department of Paediatric Medicine, John Hunter Children's Hospital, Newcastle, NSW Australia ; School of Medicine and Public Health, University of Newcastle, Newcastle, NSW Australia.
authors: Elizabeth
authors: E
authors: Percival
authors: Department of Paediatric Allergy & Immunology, John Hunter Children's Hospital, Newcastle, NSW Australia ; School of Medicine and Public Health, University of Newcastle, Newcastle, NSW Australia.
authors: Rani
authors: R
authors: Bhatia
authors: Experimental & Translational Respiratory Medicine Group, Hunter Medical Research Institute, University of Newcastle, Lookout Road, New Lambton, Newcastle, NSW 2305 Australia ; Department of Paediatric Immunology & Allergy, Starship Children's Health, Auckland, New Zealand.
authors: Kahn
authors: K
authors: Preece
authors: School of Medicine and Public Health, University of Newcastle, Newcastle, NSW Australia.
authors: Patrick
authors: P
authors: McElduff
authors: School of Medicine and Public Health, University of Newcastle, Newcastle, NSW Australia.
authors: Mark
authors: M
authors: McEvoy
authors: Experimental & Translational Respiratory Medicine Group, Hunter Medical Research Institute, University of Newcastle, Lookout Road, New Lambton, Newcastle, NSW 2305 Australia ; School of Medicine and Public Health, University of Newcastle, Newcastle, NSW Australia.
authors: Adam
authors: A
authors: Collison
authors: Experimental & Translational Respiratory Medicine Group, Hunter Medical Research Institute, University of Newcastle, Lookout Road, New Lambton, Newcastle, NSW 2305 Australia ; School of Medicine and Public Health, University of Newcastle, Newcastle, NSW Australia ; Department of Paediatric Respiratory & Sleep Medicine, John Hunter Children's Hospital, Newcastle, NSW Australia.
authors: Joerg
authors: J
authors: Mattes
keywords: Allergy; Anaphylaxis; Ara h2; Ara h2 sIgE; Fraction exhaled nitric oxide; Peanut; Peanut sIgE; Predict; Reproducibility; Skin prick test