结核分枝杆菌及利福平耐药核酸扩增检测成本分析

Cost analysis of Xpert Mtb/RIF test for the detection of M. tuberculosis and rifampin resistance

目的比较固体培养、比例法药敏和结核分枝杆菌及利福平耐药核酸扩增（XpertMtb／RIF）（简称“Xpert”）检测在中国基层实验室应用的检测成本。方法选取4个县（区）级结核病防治机构收集3次固体培养和Xpert检测成本数据，2个省参比实验室收集3次对硝基苯甲酸（PNB）菌群鉴定和比例法利福平药敏试验成本数据。采用要素法计算每种方法单位检测成本，计算每例患者不同检测方法的检测成本。在不同结核病患病率人群中，以固体培养试验为金标准，比较Xpert检测在不同检测效能下检出1例结核病患者的成本。在不同利福平耐药率的可疑人群中，以传统药敏试验为金标准，比较Xpert检测在不同检测效能下检出1例利福平耐药结核病患者的成本。调整Xpert检测设备和试剂价格后，分析Xpert检测的单位成本。结果固体培养、菌群鉴定、利福平药敏试验和Xpert检测的单位检测成本分别为47．87、46．73、82．86和118．62元。传统方法检测每例结核病患者所需成本（2份培养，1份传代，1份PNB鉴定试验）为172．57元。传统方法检测每例耐药结核病患者的平均成本（2份固体培养，1份传代，1份PNB鉴定及药敏试验）为208．84元。当Xpert检测结核病或利福平耐药特异度为85％时，如果检测敏感度大于70％，在结核病患病率或利福平耐药结核病患病率1％～70％的任何人群中，Xpert检出1例结核病或利福平耐药结核病患者的成本均低于传统方法。试剂价格变化对于检测成本的影响远远大于设备价格变化的影响。结论Xpert检测是一种比传统方法更经济并快速的检测方法，适合在中国基层实验室推广。

Objective To compare the cost of solid culture, drug susceptibility test and Xpert Mtb/RIF test in the primary laboratories in China. Methods We collected the cost data of solid culture for 3 times and Xpert Mtb/RIF test from 4 county （district） level laboratories, and strain identification and rifampin （RFP） susceptibility test for 3 times from 2 province reference laboratories. The element method was used to calculate the unit cost of each method, the detection cost of each patient. Of the population with different TB prevalence rate, the solid cul- ture was used as the gold standard to compare the cost of Xpert Mtb/RIF test to find 1 TB patient under different detection efficiency. Of the population with different rifampicin-resistant prevalence rate, the traditional drug sus- ceptibility test was used as the gold standard to compare the cost of Xpert Mtb/RIF test to find 1 RFP-resistant pa- tient under different detection efficiency. After price adjustment of Xpert Mtb/RIF detection equipment and rea- gents, the unit cost of Xpert Mtb/RIF test was analyzed. Results The unit costs of solid culture, strain identification, RFP susceptibility test and Xpert Mtb/RIF detection were 47.87, 46.73, 82.86 and 118.62 Yuan, respectively. The cost per TB patient by traditional methods （2 solid cultures, 1 sub-culture, 1 PNB strain identifi- cation） was 172.57 Yuan. The average cost of each patient with drug-resistant TB by traditional methods （2 solid cultures, 1 sub-culture, 1 PNB strain identification and 1 drug susceptibility test） was 208. 84 Yuan. When the spe- cificity of Xpert Mtb/RIF test for the detection of Mtb and RFP was 85%, its sensitivity is greater than 70%, its cost of detecting one TB case or RFP-resistant case among the population with 1% to 70% prevalence rate of TB or RFP resistance was lower than traditional methods. The influence of reagent price changes on the testing cost was far greater than the change of equipment price. Conclusion The Xpert Mtb/RIF test is a rapid and more economic method than traditional tests, and suitable for the use in the primary laboratories.