Nabeta Pamela, Havumaki Joshua, Ha Dang Thi Minh, Caceres Tatiana, Hang Pham Thu, Collantes Jimena, Thi Ngoc Lan Nguyen, Gotuzzo Eduardo, Denkinger Claudia M
FIND, Geneva, Switzerland.
TB Department, Pham Ngoc Thach Hospital, Ho Chi Minh City, Vietnam.
PLoS One. 2017 Mar 2;12(3):e0173092. doi: 10.1371/journal.pone.0173092. eCollection 2017.
Improved and affordable diagnostic or triage tests are urgently needed at the microscopy centre level. Automated digital microscopy has the potential to overcome issues related to conventional microscopy, including training time requirement and inconsistencies in results interpretation.
For this blinded prospective study, sputum samples were collected from adults with presumptive pulmonary tuberculosis in Lima, Peru and Ho Chi Minh City, Vietnam. TBDx performance was evaluated as a stand-alone and as a triage test against conventional microscopy and Xpert, with culture as the reference standard. Xpert was used to confirm positive cases.
A total of 613 subjects were enrolled between October 2014 and March 2015, with 539 included in the final analysis. The sensitivity of TBDx was 62·2% (95% CI 56·6-67·4) and specificity was 90·7% (95% CI 85·9-94·2) compared to culture. The algorithm assessing TBDx as a triage test achieved a specificity of 100% while maintaining sensitivity.
While the diagnostic performance of TBDx did not reach the levels obtained by experienced microscopists in reference laboratories, it is conceivable that it would exceed the performance of less experienced microscopists. In the absence of highly sensitive and specific molecular tests at the microscopy centre level, TBDx in a triage-testing algorithm would optimize specificity and limit overall cost without compromising the number of patients receiving up-front drug susceptibility testing for rifampicin. However, the algorithm would miss over one third of patients compared to Xpert alone.
在显微镜检查中心层面，迫切需要改进且价格合理的诊断或分诊检测方法。自动化数字显微镜有潜力克服与传统显微镜相关的问题，包括培训时间要求和结果解读的不一致性。
在这项盲法前瞻性研究中，从秘鲁利马和越南胡志明市疑似肺结核的成年人中收集痰液样本。将TBDx作为独立检测方法以及与传统显微镜检查和Xpert进行分诊检测的性能进行评估，以培养作为参考标准。使用Xpert确认阳性病例。
2014年10月至2015年3月期间共纳入613名受试者，最终分析纳入539名。与培养相比，TBDx的敏感性为62.2%（95%置信区间56.6 - 67.4），特异性为90.7%（95%置信区间85.9 - 94.2）。将TBDx评估为分诊检测的算法实现了100%的特异性，同时保持了敏感性。
虽然TBDx的诊断性能未达到参考实验室中经验丰富的显微镜检查人员所获得的水平，但可以想象它会超过经验较少的显微镜检查人员的性能。在显微镜检查中心层面缺乏高敏感性和特异性的分子检测方法的情况下，分诊检测算法中的TBDx将优化特异性并限制总体成本，而不会影响接受利福平初始药敏试验的患者数量。然而，与单独使用Xpert相比，该算法会遗漏超过三分之一的患者。
