Supplementary Material for: Comparison of the Performance of Skin Prick, ImmunoCAP, and ISAC Tests in the Diagnosis of Patients with Allergy

Background: Allergy is diagnosed from typical symptoms,
and tests are performed to incriminate the suspected precipitant. Skin
prick tests (SPTs) are commonly performed, inexpensive, and give
immediate results. Laboratory tests (ImmunoCAP) for serum
allergen-specific IgE antibodies are usually performed more selectively.
The immuno-solid phase allergen chip (ISAC) enables testing for
specific IgE against multiple allergen components in a multiplex assay. Methods:
We retrospectively analysed clinic letters, case notes, and laboratory
results of 118 patients attending the National Adult Allergy Service at
the University Hospital of Wales who presented diagnostic difficulty, to
evaluate which testing strategy (SPT, ImmunoCAP, or ISAC) was the most
appropriate to use to confirm the diagnosis in these complex patients,
evaluated in a “real-life” clinical service setting. Results:
In patients with nut allergy, the detection rates of SPTs (56%) and
ISAC (65%) were lower than those of ImmunoCAP (71%). ISAC had a higher
detection rate (88%) than ImmunoCAP (69%) or SPT (33%) in the diagnosis
of oral allergy syndrome. ImmunoCAP test results identified all 9
patients with anaphylaxis due to wheat allergy (100%), whereas ISAC was
positive in only 6 of these 9 (67%). Conclusions: In this
difficult diagnostic group, the ImmunoCAP test should be the preferred
single test for possible allergy to nuts, wheat, other specific foods,
and anaphylaxis of any cause. In these conditions, SPT and ISAC tests
give comparable results. The most useful single test for oral allergy
syndrome is ISAC, and SPT should be the preferred test for latex
allergy.

背景：过敏症的诊断基于典型临床症状，需通过相关检测明确可疑致敏原。皮肤点刺试验（Skin Prick Tests, SPTs）操作简便、成本低廉且可快速出具检测结果，是临床常用的检测手段。针对血清变应原特异性IgE抗体的实验室检测（ImmunoCAP）通常选择性开展。免疫固相变应原芯片（Immuno-solid phase allergen chip, ISAC）可通过多重检测技术，同时针对多种变应原组分检测特异性IgE抗体。
方法：本研究回顾性分析了威尔士大学医院国家成人过敏诊疗中心收治的118例存在诊断困难的患者的门诊信函、病历记录及实验室检测结果，旨在评估在真实临床诊疗场景下，何种检测策略（SPT、ImmunoCAP或ISAC）最适合用于确诊此类复杂患者的过敏病症。
结果：在坚果过敏患者中，SPT（56%）与ISAC（65%）的检出率均低于ImmunoCAP（71%）。在口腔过敏综合征的诊断中，ISAC的检出率（88%）高于ImmunoCAP（69%）与SPT（33%）。ImmunoCAP检测可100%检出9例小麦过敏引发的过敏性休克患者，而ISAC仅在其中6例呈阳性（67%）。
结论：在这类诊断难度较高的患者群体中，针对坚果、小麦及其他特定食物过敏，以及任何原因引发的过敏性休克，ImmunoCAP检测应作为首选单项检测手段。在此类场景下，SPT与ISAC的检测结果具有可比性。针对口腔过敏综合征，ISAC是最具实用价值的单项检测方式；乳胶过敏则首选SPT检测。