目的　评估外周血hsa-miR-342-5p检测对早期诊断儿童结核的价值。方法　收集初治涂片阳性、涂片阴性结核患儿，肺炎患儿和正常儿童各20例，采集静脉血，TRIzol法提取外周血总RNA，qRT-PCR检测hsa-miR-342-5p在各组间的相对表达水平，ROC曲线分析hsa-miR-342-5p诊断儿童结核的特异度和灵敏度。结果　hsa-miR-342-5p在涂片阳性结核、涂片阴性结核患儿、肺炎患儿和正常儿童四组间的差异具有统计学意义(F =21.94，P =0.00)。与正常儿童相比，hsamiR-342-5p在涂片阳性结核、涂片阴性结核和肺炎患儿中的表达水平均下调，差异有统计学意义(P 均<0.01)；与肺炎患儿相比，hsa-miR-342-5p在涂片阳性结核、涂片阴性结核患儿中的表达也明显下调，差异有统计学意义(P<0.01)。对于区分涂片阳性结核和肺炎，hsa-miR-342-5p的特异度和灵敏度性均为90%；而区分涂片阴性结核和肺炎，其特异度和灵敏度分别为65%和100%。结论　外周血hsa-miR-342-5p有望成为新的分子指标用于儿童结核的早期诊断。

　Objective 　To evaluate the value of hsa-miR-342-5p for the childhood tuberculosis (TB) diagnosis. Methods 　 Twenty culture-positive TB, 20 culture-negative TB, 20 pneumonia and 20 healthy children were enrolled in the study. The venous blood was collected. The peripheral blood total RNA was extracted by TRIzol reagent. The expression of hsa-miR-342- 5p was detected by qRT-PCR. Receiver operating characteristic (ROC) curve was used to evaluate the sensitivity and specificity of hsa-miR-342-5p to diagnose childhood TB. Results　There was a significant difference of hsa-miR-342-5p level among culture-positive TB, culture-negative TB, pneumonia and healthy controls (F=21.94, P=0.00). Compared to health control, hsamiR- 342-5p was significantly lower in culture-positive TB, culture-negative TB, and pneumonia children (P<0.01). Compared to pneumonia children, hsa-miR-342-5p was also significantly lower in culture-positive TB and culture-negative TB groups (P<0.01). For distinguish culture-positive TB and pneumonia by hsa-miR-342-5p, the sensitivity and specificity were 90% and 90% respectively. For distinguish culture-negative TB and pneumonia by hsa-miR-342-5p, the sensitivity and specificity were 65% and 100% respectively. Conclusions　 The peripheral hsa-miR-342-5p is expected to become a new biomarker for early diagnosis of tuberculosis in children.