Department of Internal Medicine, Makerere University College of Health Sciences, Ground Floor Pathology Building, Room A4, Kampala, Uganda.
Infectious Diseases Research Collaboration, Kampala, Uganda.
BMC Infect Dis. 2021 Jan 11;21(1):49. doi: 10.1186/s12879-020-05727-8.
The World Health Organization (WHO) has endorsed the next-generation Xpert MTB/RIF Ultra (Ultra) cartridge, and Uganda is currently transitioning from the older generation Xpert MTB/RIF (Xpert) cartridge to Ultra as the initial diagnostic test for pulmonary tuberculosis (TB). We assessed the diagnostic accuracy of Ultra for pulmonary TB among adults in Kampala, Uganda.
We sampled adults referred for Xpert testing at two hospitals and a health center over a 12-month period. We enrolled adults with positive Xpert and a random 1:1 sample with negative Xpert results. Expectorated sputum was collected for Ultra, and for solid and liquid culture testing for Xpert-negative patients. We measured sensitivity and specificity of Ultra overall and by HIV status, prior history of TB, and hospitalization, in reference to Xpert and culture results. We also assessed how classification of results in the new "trace" category affects Ultra accuracy.
Among 698 participants included, 211 (30%) were HIV-positive and 336 (48%) had TB. The sensitivity of Ultra was 90.5% (95% CI 86.8-93.4) and specificity was 98.1% (95% CI 96.1-99.2). There were no significant differences in sensitivity and specificity by HIV status, prior history of TB or hospitalization. Xpert and Ultra results were concordant in 670 (96%) participants, with Ultra having a small reduction in specificity (difference 1.9, 95% CI 0.2 to 3.6, p=0.01). When "trace" results were considered positive for all patients, sensitivity increased by 2.1% (95% CI 0.3 to 3.9, p=0.01) without a significant reduction in specificity (- 0.8, 95% CI - 0.3 to 2.0, p=0.08).
After 1 year of implementation, Ultra had similar performance to Xpert. Considering "trace" results to be positive in all patients increased case detection without significant loss of specificity. Longitudinal studies are needed to compare the benefit of greater diagnoses to the cost of overtreatment.
世界卫生组织（WHO）已认可新一代 Xpert MTB/RIF Ultra（Ultra）检测试剂盒，乌干达目前正从旧一代 Xpert MTB/RIF（Xpert）检测试剂盒过渡到 Ultra，将其作为肺结核（TB）的初始诊断检测方法。我们评估了 Ultra 在坎帕拉的成年人中用于肺结核的诊断准确性。
我们在两家医院和一个医疗中心对 12 个月期间进行 Xpert 检测的成年人进行了抽样。我们招募了 Xpert 阳性的成年人，并随机选择 1:1 的 Xpert 阴性结果的样本。采集咳出的痰液进行 Ultra 检测，以及对 Xpert 阴性患者进行固体和液体培养检测。我们以 Xpert 和培养结果为参照，测量了 Ultra 的整体敏感性和特异性，以及按 HIV 状态、既往结核病史和住院情况进行分层的敏感性和特异性。我们还评估了新的“微量”类别中结果分类如何影响 Ultra 的准确性。
在纳入的 698 名参与者中，有 211 名（30%）为 HIV 阳性，336 名（48%）患有结核病。Ultra 的敏感性为 90.5%（95%CI 86.8-93.4），特异性为 98.1%（95%CI 96.1-99.2）。按 HIV 状态、既往结核病史或住院情况，敏感性和特异性无显著差异。在 670 名（96%）参与者中，Xpert 和 Ultra 结果一致，Ultra 的特异性略有下降（差异 1.9，95%CI 0.2 至 3.6，p=0.01）。当所有患者的“微量”结果均被视为阳性时，敏感性增加了 2.1%（95%CI 0.3 至 3.9，p=0.01），而特异性无显著下降（-0.8，95%CI-0.3 至 2.0，p=0.08）。
实施一年后，Ultra 的性能与 Xpert 相似。将所有患者的“微量”结果视为阳性可提高病例检出率，而特异性无明显损失。需要进行纵向研究来比较增加诊断的益处与过度治疗的成本。
