title: Oral peanut challenge identifies an allergy but the peanut allergen threshold sensitivity is not reproducible.
abstract: BACKGROUND
  Double-blind placebo-controlled food challenge, DBPCFC, the gold standard for diagnosing food allergy, is time-consuming and potentially dangerous. A basophil allergen threshold sensitivity test, CD-sens, has shown promising results as a diagnostic tool in food allergy.
  
  
  OBJECTIVE
  To evaluate the reproducibility of oral peanut challenge and compare the outcome to CD-sens in peanut-sensitized children.
  
  
  METHODS
  Twenty-seven children (4-19 years) underwent a DBPCFC followed by a single-blind oral food-challenge. The peanut challenges (1 mg to 5 g) were evaluated by severity scoring. Blood samples were drawn for CD-sens before the two first challenges.
  
  
  RESULTS
  Thirteen children (48%) did not react at any of the challenges. Fourteen reacted at both peanut challenges but not to placebo. Only two of these children reacted at the same threshold dose and with the same severity score. All other children scored differently or reacted at different doses. For children with a positive challenge the geometric mean of the ratio of the doses was 1.834 (p = 0.307) and the arithmetic mean of the difference between the severity scores was 0.143 (p = 0.952). No association was obtained between the two peanut challenges regarding severity score (r(s) = 0.11, p = 0.71) or threshold dose (r(s) = 0.35, p = 0.22). Among the children positive in peanut challenge, 12 were positive in CD-sens. Two were low-responders and could not be evaluated. Geometric mean of the ratio of CD-sens values in children with a positive challenge was 1.035 (p = 0.505) but unlike for the severity score and the threshold dose the association between the two CD-sens values was strong (r(s) = 0.94, P<0.001).
  
  
  CONCLUSIONS
  For a positive/negative test the reproducibility is 100% for both peanut challenge and CD-sens. However, a comparison of the degree of allergen threshold sensitivity between the two tests is not possible since the threshold dose and severity scoring is not reproducible.
authors: Department of Clinical Science and Education, Södersjukhuset, Centre for Allergy Research, Karolinska Institutet, Stockholm, Sweden. susanne.glaumann@sodersjukhuset.se
authors: Susanne
authors: S
authors: Glaumann
authors: Anna
authors: A
authors: Nopp
authors: S G O
authors: SG
authors: Johansson
authors: Magnus P
authors: MP
authors: Borres
authors: Caroline
authors: C
authors: Nilsson
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D000485:Allergens / Q000008:administration & dosage* / Q000276:immunology*; D010367:Arachis / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007159:Immunologic Tests; D008297:Male; D021183:Peanut Hypersensitivity / Q000276:immunology*; D015203:Reproducibility of Results; D055815:Young Adult
chemical_list: D000485:Allergens