Abstract:

Objective Objective evaluation of allergic rhinitis(AR) requires in vivo skin prick test(SPT) and in vitro serum specific IgE(sIgE) tests. It is important to explore the relationship between the SPT and sIgE for promoting the AR diagnosis efficiency. The aim of this study was to investigate the influence of different cut-off values for positivity of SPT in the evaluation of sIgE in the diagnosis of multi-allergens AR patients. Methods Combining a positive SPT and clinical history and nasal local signs as the diagnostic reference criteria of AR, we estimated concentrations of serum sIgE produced in response to the 7 most common allergens among 85 AR patients, using "+" and "++" positive cut-off value of SPT respectively. Results Based on a clinical diagnosis and SPT results using a positive cut-off value of "+", the serum sIgE test performed well and the sensitivity for different allergens ranged from 0.50(giant ragweed) to 0.91 dermatophagoides pterongssinus and dermatophagoides farinae(Der p and Der f), while specificity ranged from 0.93(Der f) to 1.00(animal hair, Der p and mugwort). When adjusting the cut-off score to "++", the sensitivity showed an overall increase while the remaining assessed items, including specificity, positive predictive value, negative predictive value and efficiency, showed an unacceptable decline. Conclusion Setting "+" cut-off for positivity of SPT results was better than "++" setting for assessing the AR diagnosis value of serum sIgE.

Key words: allergic rhinitis, diagnosis, specific-immunoglobulin E, skin prick test