Wang Guirong, Wang Shuqi, Jiang Guanglu, Fu Yuhong, Shang Yuanyuan, Huang Hairong
National Clinical Laboratory for Tuberculosis, Beijing Key laboratory for Drug-resistant Tuberculosis Research, Beijing Chest Hospital, Capital Medical University, Beijing Tuberculosis and Thoracic Tumor Institute, Beijing 101149, China.
J Thorac Dis. 2018 Mar;10(3):1689-1695. doi: 10.21037/jtd.2018.02.60.
Due to the non-homogeneity of specimens collected from tuberculosis (TB) suspects, repeated Xpert MTB/RIF (Xpert) may have potential clinical benefits. Incremental cost-effectiveness was analyzed for the second Xpert assay to detect (Mtb) and rifampicin (RIF) resistance.
Specimens were collected from 1,063 pulmonary TB (PTB) and 398 extrapulmonary TB (EPTB) suspects, who had two Xpert tests sequentially within one week. The specimens were subjected to smear, culture, Xpert and drug susceptibility testing. Incremental cost-effectiveness of the serial Xpert assays was evaluated.
Among 813 Xpert-positive TB patients, 755 (92.87%) were identified by the first assay whereas the additional 58 (7.13%) were identified by the second assay. The second Xpert assay had higher incremental yield for smear-negative than for smear-positive specimens (12.07% 1.84%, P<0.001), and higher incremental yield for EPTB than for PTB (10.71% 4.65%, P=0.003). About 94.48% (137/145) of the RIF-resistant patients were identified by the first Xpert assay and 5.52% (8/145) were identified by the second Xpert assay. After the first assay, the incremental cost of performing a second Xpert was huge: US$22.82 US$467.72 (P<0.001) and US$35.02 US$291.87 (P<0.001) for PTB and EPTB, respectively. The incremental cost of performing a second Xpert is lower in smear-negative than in smear-positive group in both PTB and EPTB.
One Xpert assay is sufficient for smear-positive cases, and a second Xpert assay is beneficial not only for Mtb detection but also for RIF-resistant diagnosis for smear-negative TB suspects, whereas the incremental cost for the second Xpert is huge.
由于从结核病（TB）疑似患者采集的样本存在异质性，重复进行Xpert MTB/RIF检测（Xpert）可能具有潜在的临床益处。对第二次Xpert检测以检测结核分枝杆菌（Mtb）和利福平（RIF）耐药性的增量成本效益进行了分析。
从1063例肺结核（PTB）和398例肺外结核（EPTB）疑似患者中采集样本，这些患者在一周内依次进行了两次Xpert检测。对样本进行涂片、培养、Xpert检测和药敏试验。评估了连续Xpert检测的增量成本效益。
在813例Xpert检测阳性的结核病患者中，755例（92.87%）通过首次检测确诊，另外58例（7.13%）通过第二次检测确诊。第二次Xpert检测对涂片阴性样本的增量检出率高于涂片阳性样本（12.07%对1.84%，P<0.001），对EPTB的增量检出率高于PTB（10.71%对4.65%，P=0.003）。约94.48%（137/145）的耐RIF患者通过首次Xpert检测确诊，5.52%（8/145）通过第二次Xpert检测确诊。首次检测后，进行第二次Xpert检测的增量成本巨大：PTB为22.82美元至467.72美元（P<0.001），EPTB为35.02美元至291.87美元（P<0.001）。在PTB和EPTB中，涂片阴性组进行第二次Xpert检测的增量成本均低于涂片阳性组。
对于涂片阳性病例，一次Xpert检测就足够了，而第二次Xpert检测不仅有利于Mtb检测，也有利于涂片阴性TB疑似患者的耐RIF诊断，然而第二次Xpert检测的增量成本巨大。
