%0 Journal Article %A Bjørg Evjenth %A Tonje Elisabeth Hansen %A Ole-Lars Brekke %A Jan Holt %T The diagnostic accuracy of allergen-specific IgE and its relation to exhaled nitric oxide in children %D 2014 %J European Respiratory Journal %P P4205 %V 44 %N Suppl 58 %X Background: Cut-off values for serum allergen-specific IgE (sIgE) using the Siemens IMMULITE®2000 system to diagnose allergic rhinoconjunctivitis have not been established in children. Likewise the relation between sgE, total IgE and fraction exhaled nitric oxide (FENO) has not been fully elucidated in a subarctic children population.Aims: We aimed to determine cut-off levels of sIgE for ten common inhalant allergens and to study the relationship between sIgE, total IgE and FENO.Methods: We enrolled 243 schoolchildren including 164 with allergic rhinoconjunctivitis. Parental interview, skin prick test, sIgE, total IgE, FENO measurements, spirometry and exercise treadmill tests were performed.Results: Cut-off values with the best combined sensitivity and specificity were above the detection limit of the assay for seven of ten allergens (0.23-1.1 kU/L). The overall accuracy of IMMULITE® in detecting allergic rhinoconjunctivitis was good. sIgE was superior to total IgE and FENO in predicting allergic rhinoconjunctivitis to timothy, birch, mugwort, cat, dog and house dust mite. FENO was elevated in children with allergic rhinoconjunctivitis, irrespective of asthma. FENO was highest in children with current allergic asthma 29.7 (23.3-37.7) ppb.Conclusions: Cut-off values for sIgE were dependent on the allergic phenotype and were above the IMMULITE® detection limit for seven of ten inhalant allergens. Consequently, using the detection limit for sIgE as the decision point would result in over-diagnosing allergic rhinoconjunctivitis. When measuring elevated FENO in children, allergic rhinoconjunctivitis should be suspected.The manuscript has been submitted to ACTA Paediatrica. %U