BACKGROUND The clinical presentation of celiac disease (CD) varies between children. The objective of this study was to document the pre-test probability for CD based on symptoms and routine laboratory test and to evaluate the performance of two IgA anti-tissue transglutaminase (tTG) assays. We critically reviewed the concept of using multiples of the manufacturer's upper limit of normal (ULN), as proposed in the ESPGHAN guidelines (if IgA tTG is >10 times ULN, no biopsy is needed). METHODS The retrospective study included 91 children with newly diagnosed CD and 605 controls (<16 years). All underwent upper endoscopy with small bowel biopsies. Four laboratory parameters and 16 symptoms were registered. All patients were tested for IgA anti-tTG antibodies with assays from Inova Diagnostics and Thermo Fisher Scientific. RESULTS Some combinations of clinical symptoms and laboratory parameters had a high pre-test probability for CD, such as (combinations of) anorexia, failure to thrive, low ferritin level and elevated AST. The diagnostic performance of both IgA anti-tTG assays was excellent and comparable (no difference in ROC curve area under the curve). At a threshold that corresponds to a specificity of 100% (5 times ULN for Inova Diagnostics and 2 times ULN for Thermo Fisher), the sensitivity was 82% for both assays. At the 10 times ULN threshold, the sensitivity differed between the assays (77% vs. 57%), indicating that such threshold does not completely align interpretation across companies. CONCLUSIONS Our study showed that some combinations of symptoms and aberrant laboratory parameters had a high pre-test probability. The use of the ESPGHAN non-biopsy approach could reduce small bowel biopsies, but thresholds for IgA-tTG levels are not aligned across assays and should be based on predefined likelihood ratios or specificity.

中文翻译：

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小儿腹腔疾病的血清学诊断优化。

背景技术乳糜泻（CD）的临床表现因儿童而异。这项研究的目的是根据症状和常规实验室检查来记录CD的预检概率，并评估两种IgA抗组织转谷氨酰胺酶（tTG）检测的性能。我们严格审查了使用ESPGHAN指南中建议的制造商正常上限（ULN）倍数的概念（如果IgA tTG大于ULN的10倍，则无需进行活检）。方法回顾性研究包括91名新诊断为CD的儿童和605名对照（<16岁）。所有患者均接受上消化道内镜检查和小肠活检。记录了四个实验室参数和16个症状。使用Inova Diagnostics和Thermo Fisher Scientific的检测方法对所有患者的IgA抗tTG抗体进行了测试。结果临床症状和实验室参数的某些组合对CD的检测前可能性很高，例如（厌食症），failure壮失败，铁蛋白水平低和AST升高。两种IgA抗tTG分析的诊断性能均极佳且具有可比性（曲线下ROC曲线面积无差异）。在对应于100％特异性的阈值（对于Inova Diagnostics，是ULN的5倍，对于Thermo Fisher来说，ULN的2倍），两种测定的灵敏度均为82％。在10倍ULN阈值下，各测定之间的灵敏度有所不同（77％对57％），这表明该阈值并未完全符合公司的解释。结论我们的研究表明，症状和实验室参数异常的某些组合具有较高的预测试概率。