Objective: To evaluate the diagnostic value of hydrogen sulfide breath test(SBT) for small intestinal bacterial overgrowth (SIBO). Methods: College students were enrolled to complete gastrointestinal symptom scale, food frequency questionnaire, lactulose hydrogen- methane breath test (LHMBT) and SBT. Based on the correlation between hydrogen sulfide(H2S) and hydrogen or methane gas,the receiver operating characteristic (ROC) curve of H2S was drawn and diagnostic criteria of SBT was defined. Results: A total of 300 subjects including 84 males and 216 females with age 17-32 (21.6±2.4) years were enrolled from April 2019 to December 2019 and divided into two groups.Two hundred and three patients reported SIBO discomforts with 99 (48.8%) LHMBT positive, while 38 (39.2%) were LHMBT positive in 97 health controls. Rise of H2S at 90 min was positively related with that of hydrogen (r=0.516, P<0.01), and H2S levels at 90 min were positively correlated with methane (r=0.632, P<0.01). A rise in H2S of ≥25.0 ppb or H2S levels ≥62.5 ppb at 90 min during lactulose breath test was considered positive for SIBO, that sensitivity, specificity and accuracy were 66.4%,79.1% and 73.3% respectively. H2S levels were significantly related to the amount of Vitamin B12 intake (P=0.011). H2S-positive subjects exhibited a constipation-predominant pattern. Conclusion: SBT is consistent with LHMBT, especially in constipation-predominant patients, which may provide a reference to the diagnosis of SIBO.
目的： 探究硫化氢呼气试验（hydrogen sulfide breath test，SBT）在小肠细菌过度生长（small intestinal bacterial overgrowth， SIBO）诊断中的应用价值。 方法： 纳入2019年4—12月某高校学生，进行消化道症状和1周膳食问卷调查，以及乳果糖氢-甲烷呼气试验（lactulose hydrogen-methane breath test，LHMBT）和SBT。分析呼气中氢、甲烷及硫化氢浓度并绘制硫化氢的受试者工作特征（ROC）曲线，确定SBT的阳性判断标准。 结果： 共纳入300名受试者，男84名、女216名，年龄17~32（21.6±2.4）岁。203名报告SIBO样症状，其中LHMBT阳性99名（48.8%）；无症状97名中，LHMBT阳性38名（39.2%）。摄入乳果糖90 min时呼气中硫化氢升高值和氢气升高值显著正相关（r=0.516，P<0.01）；硫化氢绝对值和甲烷浓度显著正相关（r=0.632，P<0.01）。以服用乳果糖后90 min时硫化氢绝对值≥62.5 ppb（×10-9）或较基线值升高25.0 ppb为阳性判断值，敏感度、特异度和准确率分别为66.4%、79.1%和73.3%。硫化氢丰度与维生素B12的摄入量显著相关（P=0.011），阳性者便秘更为突出。 结论： 乳果糖硫化氢呼气试验与氢-甲烷具有较高的一致性，对便秘患者具有更高的检出率，可作为诊断SIBO的重要补充。.