Translational Research Center for Gastrointestinal Disorders, KU Leuven, Herestraat 49, 3000, Leuven, Belgium.
Department of Laboratory Medicine Cosis, University Hospitals Leuven, Leuven, Belgium.
Dig Dis Sci. 2024 Jun;69(6):2147-2153. doi: 10.1007/s10620-024-08304-0. Epub 2024 Mar 18.
Diagnosing lactose malabsorption is usually based on hydrogen excretion in breath after a lactose challenge. However, a proportion of subjects with lactose malabsorption will not present a rise in hydrogen. Measuring excretion of methane or stable isotope labeled CO after ingestion of C-lactose has been proposed to mitigate this problem.
The aim of the study was to assess the performance of measuring methane and CO in individuals with normal hydrogen excretion compared to a genetic lactase non-persistence test.
Individuals referred for lactose breath testing and healthy controls were included. Participants received C-enriched lactose, performed breath testing, and underwent genotyping for a marker of lactase non-persistence (13910C*T). Using genotype as gold standard, the performance of measuring methane and CO excretion was assessed.
151 subjects participated in the study, 50 of which presented a lactase non-persistent genotype. Of these, 72% were correctly diagnosed through hydrogen excretion of ≥ 20 ppm above baseline. In subjects with normal hydrogen excretion, cumulative C excretion had an area under the curve (AUC) of the receiver operating characteristics (ROC) curve of 0.852. Sensitivity was 93% and specificity was 51% for the current cutoff of 14.5%. The optimal cutoff was 12.65% (sensitivity 93%, specificity 70%). The ROC curve of peak methane had an AUC of 0.542 (sensitivity of 14%, specificity of 91% for cutoff ≥ 10 ppm).
In individuals with genetically demonstrated lactase non-persistence and negative hydrogen breath test, the use of C-lactose with measurement of CO excretion and hydrogen is a well-performing test to detect the lactose malabsorption and performs better than methane in our cohort.
乳糖吸收不良的诊断通常基于乳糖负荷后呼气中的氢气排泄。然而，一部分乳糖吸收不良的患者呼气中的氢气不会升高。摄入 C-乳糖后测量甲烷或稳定同位素标记的 CO 的排泄已被提出用于缓解此问题。
本研究旨在评估与乳糖酶非持续型基因检测相比，测量正常氢排泄个体中甲烷和 CO 排泄的性能。
纳入因乳糖呼气试验而就诊的个体和健康对照者。参与者接受 C 标记乳糖，进行呼气测试，并进行乳糖酶非持续型的基因检测（13910C*T）。使用基因型作为金标准，评估测量甲烷和 CO 排泄的性能。
151 名受试者参与了研究，其中 50 名受试者存在乳糖酶非持续型基因型。其中，72%的患者通过氢排泄值比基线升高≥20ppm而得到正确诊断。在氢排泄正常的受试者中，C 排泄的累积量的受试者工作特征（ROC）曲线的曲线下面积（AUC）为 0.852。当前 14.5%的截止值的灵敏度为 93%，特异性为 51%。最佳截止值为 12.65%（灵敏度 93%，特异性 70%）。峰甲烷的 ROC 曲线 AUC 为 0.542（截止值≥10ppm时的灵敏度为 14%，特异性为 91%）。
在具有基因证实的乳糖酶非持续型和阴性氢呼气试验的个体中，使用 C-乳糖并测量 CO 排泄和氢是一种性能良好的检测乳糖吸收不良的方法，在我们的队列中比甲烷的性能更好。
