过敏性鼻炎皮肤点刺试验阳性界值对血清特异性IgE诊断价值的影响

目的对过敏性鼻炎(allergic rhinitis,AR)的客观评估包括体内皮肤点刺试验(skin prick test,SPT)和体外血清特异性IgE(serum specific IgE,sIgE)检测,了解SPT、sIgE试验在诊断AR中的关系对于提高AR的诊断效率至关重要。本研究旨在评估在多过敏原导致的过敏性鼻炎中,不同的SPT阳性界值对血清sIgE诊断价值的影响。方法以SPT结合的阳性结果临床症状和体征作为诊断AR的参考标准,在85例由7种常见过敏原所致的AR患者中,评估SPT阳性界值"+"和"++"对于UniCAP系统检测血清sIgE诊断价值的影响,诊断指标包括灵敏性、特异性、阳性预测值、阴性预测值和诊断效率。结果依据临床症状和体征以及SPT结果"+"作为阳性临界值诊断AR,血清sIgE检测结果良好,其灵敏性在0.50(大豚草)到0.91(屋尘螨、粉尘螨)之间,而特异性在0.93(粉尘螨)到1.00(动物毛、屋尘螨和艾蒿)之间。当SPT阳性临界值调至"++"时,sIgE的整体灵敏性提高,而其余的诊断指标,如特异性、阳性预测值、阴性预测值和诊断效率均明显下降。结论在AR的诊断中,将SPT阳性的临界值设为"+"比"++"更有益于提高血清sIgE的诊断价值。

Influence of cut-off value of skin prick test on the evaluation of serum specific IgE in the diagnosis of allergic rhinitis

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.