National Tuberculosis Institute, Bangalore, India.
International Union Against Tuberculosis and Lung Disease (The Union), Paris, France.
PLoS One. 2021 Jan 6;16(1):e0244785. doi: 10.1371/journal.pone.0244785. eCollection 2021.
As per national policy, all diagnosed tuberculosis patients in India are to be tested using Xpert® MTB/RIF assay at the district level to diagnose rifampicin resistance. Regardless of the result, samples are transported to the reference laboratories for further testing: first-line Line Probe Assay (FL-LPA) for rifampicin-sensitive samples and second-line LPA(SL-LPA) for rifampicin-resistant samples. Based on the results, samples undergo culture and phenotypic drug susceptibility testing. We assessed among patients diagnosed with tuberculosis at 13 selected Xpert laboratories of Karnataka state, India, i) the proportion whose samples reached the reference laboratories and among them, proportion who completed the diagnostic algorithm ii) factors associated with non-reaching and non-completion and iii) the delays involved.
This was a cohort study involving review of programme records. For each TB patient diagnosed between 1st July and 31st August 2018 at the Xpert laboratory, we tracked the laboratory register at the linked reference laboratory until 30th September (censor date) using Nikshay ID (a unique patient identifier), phone number, name, age and sex.
Of 1660 TB patients, 1208(73%) samples reached the reference laboratories and among those reached, 1124(93%) completed the algorithm. Of 1590 rifampicin-sensitive samples, 1170(74%) reached and 1104(94%) completed the algorithm. Of 64 rifampicin-resistant samples, only 35(55%) reached and 17(49%) completed the algorithm. Samples from rifampicin-resistant TB, extra-pulmonary TB and two districts were less likely to reach the reference laboratory. Non-completion was more likely among rifampicin-resistant TB and sputum-negative samples. The median time for conducting and reporting results of Xpert® MTB/RIF was one day, of FL-LPA 5 days and of SL-LPA16 days.
These findings are encouraging given the complexity of the algorithm. High non-reaching and non-completion rates in rifampicin-resistant patients is a major concern. Future research should focus on understanding the reasons for the gaps identified using qualitative research methods.
根据国家政策，印度所有确诊的肺结核患者都要在地区一级使用 Xpert® MTB/RIF 检测进行利福平耐药性检测。无论检测结果如何，样本都要运送到参考实验室进行进一步检测：利福平敏感样本的一线探针分析（FL-LPA）和利福平耐药样本的二线探针分析（SL-LPA）。根据检测结果，样本要进行培养和表型药敏检测。我们评估了印度卡纳塔克邦 13 个选定的 Xpert 实验室确诊的肺结核患者，i）样本到达参考实验室的比例，以及在这些样本中完成诊断算法的比例；ii）与未到达和未完成相关的因素；iii）涉及的延迟。
这是一项队列研究，涉及方案记录的审查。对于 2018 年 7 月 1 日至 8 月 31 日在 Xpert 实验室确诊的每位结核病患者，我们使用 Nikshay ID（唯一的患者标识符）、电话号码、姓名、年龄和性别，跟踪与实验室关联的参考实验室的实验室登记册，直到 9 月 30 日（截止日期）。
在 1660 例结核病患者中，有 1208 例（73%）样本到达参考实验室，在到达的样本中，有 1124 例（93%）完成了该算法。在 1590 例利福平敏感样本中，有 1170 例（74%）到达并完成了算法，1104 例（94%）到达并完成了算法。在 64 例利福平耐药样本中，只有 35 例（55%）到达，17 例（49%）完成了算法。来自利福平耐药结核病、肺外结核病和两个地区的样本到达参考实验室的可能性较低。利福平耐药结核病和痰阴性样本的非完成率更高。Xpert® MTB/RIF 的检测和报告结果中位数为 1 天，FL-LPA 为 5 天，SL-LPA 为 16 天。
鉴于算法的复杂性，这些发现令人鼓舞。利福平耐药患者的高未到达和未完成率是一个主要问题。未来的研究应侧重于使用定性研究方法了解确定的差距的原因。
