目的 对3例骨髓涂片阴性黑热病患儿的病原学宏基因组二代测序技术（mNGS）检测结果进行分析，探讨mNGS在临床的应用价值。方法 回顾性分析2021年4月至2022年2月PICU收集的3例骨髓涂片阴性患儿黑热病的临床资料。结果 3例患儿中女2例，男1例，年龄均<3岁。均有发热，骨髓涂片均阴性，外周血mNGS检测均提示利什曼原虫感染，且未见其他病原感染，经葡萄糖酸锑治疗后均治愈。结论 骨髓涂片阴性的婴幼儿黑热病早期诊断困难。对于临床感染性疾病，尤其是常规检测无法确定病原的疑难危重的感染性疾病，mNGS能提供快速准确的病原学诊断支持，助力精准诊治。

Objective To analyze the pathogen of 3 kala-azar infants with negative bone marrow smear by metagenomics next-generation sequencing (mNGS), and to explore the clinical application value of mNGS. Methods Clinical data of 3 pediatric cases of infant kala-azar with negative bone marrow smear collected in PICU from April 2021 to February 2022 were restrospectively analyzed. Results Two of the three infants were girls and one was a boy, all under the age of three. All had fever, negative bone marrow smears, peripheral blood mNGS tests suggestive of Leishmania protozoa infection, and no other pathogenic infections were observed; all were cured after antimony gluconate treatment. Conclusions Early diagnosis of infant kala-azar with negative bone marrow smear is difficult. mNGS can provide rapid and accurate pathogenetic diagnostic support and aid in precise diagnosis and treatment for clinical infectious diseases, particularly complicated and critical infectious diseases whose pathogens cannot be determined by routine testing.