St. Anna Kinderspital.
Abteilung für Gastroenterologie und Hepatologie, Universitätsklinik für Innere Medizin 3; Medical University of Vienna, Austria.
J Pediatr Gastroenterol Nutr. 2021 Mar 1;72(3):e71-e77. doi: 10.1097/MPG.0000000000003004.
The relevance of methane measurement in breath tests for the detection of carbohydrate malabsorption in children is controversial. The need for correction for poor sample collection is disputed. We evaluated the relevance of methane/CO2 measurements for the diagnosis of paediatric carbohydrate malabsorption.
A total of 132 breath tests (fructose: n = 54; lactose: n = 78) were performed in 91 children/adolescents with functional abdominal complaints. Breath samples were collected and analysed for hydrogen, methane, and CO2. Malabsorption was defined by a net increase over baseline of ≥20 parts per million (ppm) for hydrogen, ≥5 to ≥12 ppm for methane, and ≥10 to ≥15 ppm for hydrogen-plus-methane. The diagnosis was made before and after the use of a CO2-based correction factor (5.5% as the numerator). Hydrogen-based test results were compared with results obtained with other cut-off values.
Fifty-eight positive tests were obtained by hydrogen measurement (without CO2 correction). The addition of methane measurements did not significantly influence the test results (P > 0.05). Only under the use of extraordinary cut-offs (combined hydrogen-plus-methane smaller than ≥18 ppm) did the rate of malabsorbers increase significantly (P < 0.05). After CO2 correction, hydrogen ≥20 ppm was detected in 4 additional patients, but 1 patient lost the hydrogen-based diagnosis of malabsorption (Cohen kappa = 0.92).
Methane measurement did not significantly affect the detection rate of carbohydrate malabsorbers in children/adolescents with functional abdominal complaints when established cut-offs are used. The use of CO2 correction altered the diagnosis of malabsorption in a minority of patients but did not significantly alter overall test results.
甲烷测量在儿童碳水化合物吸收不良检测中的应用的相关性存在争议。对于样本采集不良是否需要校正存在争议。我们评估了甲烷/CO2 测量对儿童碳水化合物吸收不良的诊断价值。
对 91 例有功能性腹部不适的儿童/青少年进行了 132 项呼吸试验（果糖：n=54；乳糖：n=78）。收集并分析了氢、甲烷和 CO2 的呼气样本。吸收不良的定义为氢的基线净增加≥20 ppm，甲烷的基线净增加≥5 至≥12 ppm，氢加甲烷的基线净增加≥10 至≥15 ppm。在使用基于 CO2 的校正因子（5.5%作为分子）之前和之后做出诊断。将氢基测试结果与其他截断值的结果进行比较。
通过氢测量得到 58 个阳性测试（无 CO2 校正）。甲烷测量的加入并未显著影响测试结果（P>0.05）。只有在使用特殊截断值（氢加甲烷小于≥18 ppm）的情况下，吸收不良者的比例才显著增加（P<0.05）。CO2 校正后，又有 4 例患者的氢≥20 ppm，但有 1 例患者失去了基于氢的吸收不良诊断（Cohen kappa=0.92）。
在使用既定截断值时，甲烷测量对功能性腹部不适儿童/青少年碳水化合物吸收不良的检出率无显著影响。CO2 校正改变了少数患者的吸收不良诊断，但并未显著改变整体测试结果。
