Will more sensitive diagnostics identify tuberculosis missed by clinicians? Evaluating Xpert MTB/RIF testing in Guatemala

ObjectiveTo assess the impact of introducing Xpert as a follow-on test after smear microscopy on the total number pulmonary TB notifications.MethodGenexpert systems were installed in six departments across Guatemala, and Xpert was indicated as a follow-on test for people with smear-negative results. We analyzed notifications to national tuberculosis (TB) programmes (NTP) and the project's laboratory data to assess coverage of the intervention and case detection yield. Changes in quarterly TB notifications were analyzed using a simple pre/post comparison and a regression model controlling for secular notification trends. Using a mix of project and NTP data we estimated the theoretical yield of the intervention if testing coverage achieved 100%.ResultsOver 18,000 smear-negative individuals were eligible for Xpert testing during the intervention period. Seven thousand, one hundred and ninety-three people (39.6% of those eligible) were tested on Xpert resulting in the detection of 199 people with smear-negative, Xpert positive results (2.8% positivity rate). In the year before testing began 1098 people with smear positive and 195 people with smear negative results were notified in the six intervention departments. During the intervention, smear-positive notification remained roughly stable (1090 individuals, 0.7%), but smear-negative notifications increased by 167 individuals (85.6%) to an all-time high of 362. After controlling for secular notifications trends over an eight-quarter pre-intervention period, combined pulmonary TB notifications (both smear positive and negative) were 19% higher than trend predictions. If Xpert testing coverage approached 100% of those eligible, we estimate there would have been a + 41% increase in TB notifications.ConclusionsWe measured a large gain in pulmonary notifications through the introduction of Xpert testing alone. This indicates a large number of people with TB in Guatemala are seeking health care and being tested, yet are not diagnosed or treated because they lack bacteriological confirmation. Wider use of more sensitive TB diagnostics and/or improvements in the number of people clinically diagnosed with TB have the potential to significantly increase TB notifications in this setting, and potentially in other settings where a low proportion of pulmonary notifications are clinically diagnosed.     

灌洗液Xpert MTB/RIF检测在涂片阴性及无痰疑似肺结核患者中的应用分析

目的 探讨灌洗液Xpert MTB/RIF检测在涂片阴性及无痰疑似肺结核患者中的诊断效能.方法 选取河南省胸科医院结核科2020年1月1日至2020年6月30日期间收治的疑似肺结核患者98例为研究对象,留取气管镜灌洗液行抗酸染色、Xpert MTB/RIF检测、分枝杆菌液体培养,以灌洗液分枝杆菌液体培养结果、病理诊断结...     

The impact of changing the diagnostic algorithm for TB in Manicaland,Zimbabwe

SETTING:Governmental health facilities performing TB diagnostics in Manicaland, Zimbabwe.OBJECTIVE:To investigate the effect of making Xpert® MTB/RIF the primary TB diagnostic for all patients presenting with presumptive TB on 1) the number of samples investigated for TB, 2) the proportion testing TB-positive, and 3) the proportion of unsuccessful results over time.DESIGN:This retrospective study used data from GeneX-pert downloads, laboratory registers and quality assurance reports between 1 January 2017 and 31 December 2018.RESULTS:The total number of Xpert tests performed in Manicaland increased from 3,967 in the first quarter of 2017 to 7,011 in the last quarter of 2018. Mycobacterium tuberculosis DNA was detected in 4.9–8.6% of the samples investigated using Xpert, with a higher yield in 2017 than in 2018. The overall proportion of unsuccessful Xpert assays due to “no results”, errors and invalid results was 6.3%, and highly variable across sites.CONCLUSION:Roll out of more sensitive TB diagnostics does not necessarily result in an increase of microbiologically confirmed TB diagnosis. While the number of samples tested using Xpert increased, the proportion of TB-positive tests decreased. GeneXpert soft- and hardware infrastructure needs to be strengthened to reduce the rate of unsuccessful assays and therefore, costs and staff time.     

血清MMP-9测定、肺泡灌洗液Xpert MTB/RIF检测、INF-γ释放试验单独和联合检测对肺结核的诊断效能

目的 探讨血清基质金属蛋白酶-9(MMP-9)测定联合肺泡灌洗液Xpert MTB/RIF检测、γ-干扰素(INF-γ)释放试验对肺结核的诊断效能.方法 选取2019年5月—2020年5月河北省胸科医院200例疑似肺结核患者,根据检查结果分为菌阳肺结核组(62例)、菌阴肺结核组(88例)、非肺结核组(50例),比较3组...     

339例疑似肺结核患者Xpert Mtb/RIF检测临床分析

目的：探讨基层医院对结核病快速检测的方法。方法：收集2014年全年结核病门诊入选国家免费项目患者的痰标本,进行Xpert Mtb/RIF检测、荧光显微镜涂片找抗酸杆菌,并将二者进行对比,以培养做为最终标准。对结果进行分析。结果：对339份标本进行Xpert Mtb/RIF,荧光镜抗酸染色及培养,其中检测组175例患者标本中,阳性标本123例,阳性率为70.3%;对照组164中涂片阳性标本58例,阳性率为35.4%。卡方检验结果表明两组有显著性差异（P<0.01）。针对两种方法的阳性标本进行固体培养,培养结果为：Xpert Mtb/RIF检测阳性123例标本,阳性为80例,阳性率为70.3%。对照组阳性标本58例,培养出细菌19例,阳性率为19.3%卡方检验结果表明两组显著性差异（P<0.01）。结论：Xpert Mtb/RIF方法能快速、方便、灵敏检测结核杆菌,并快速培养出结核杆菌及耐药分析。     

Testing for high‐risk HPV in cervical and tonsillar paraffin‐embedded tissue using a cartridge‐based assay

This study evaluates the suitability of Xpert HPV (Cepheid, Sunnyvale, CA, USA) test for cervical and tonsillar formalin‐fixed paraffin‐embedded (FFPE) tissue samples as compared to the tests currently used in diagnostics. Cervical biopsies and liquid cytology (LC) samples were collected from 48 women attending colposcopy. Biopsies were processed for histology and tested for hrHPV using Xpert HPV. LC samples were tested using Xpert and Hybrid Capture 2 (HC2; Qiagen, Hilden, Germany) tests. Also 29 archived tonsillar carcinoma samples were tested using Xpert, and the results were compared with histology and immunohistochemical p16INK4a (p16) staining. Among valid cervical LC samples 46.8% were hrHPV positive using Xpert test and 55.3% with HC2. The sensitivity of Xpert was 84.6% as compared to HC2, and overall test concordance was 91.5%. Test concordance between valid Xpert results from biopsies and LC samples was 84.6%. Among valid tonsillar samples 70.4% were hrHPV positive, and concordance of 96.3% was found between Xpert and p16 staining. To conclude, Xpert HPV test cartridge provides a convenient platform to test individual samples, including FFPE samples. Further studies are needed to establish whether test sensitivity is sufficient to reliably differentiate between hrHPV positive and hrHPV negative head and neck carcinomas.     

Xpert MTB/RIF对初治涂阴肺结核支气管肺泡灌洗液检测的研究

目的 探讨Xpert MTB/RIF检测支气管肺泡灌洗液对初治涂阴肺结核的早期快速诊断价值。方法 对南通市第六人民医院2015年6月—2018年1月连续三次痰涂片阴性的疑似初治肺结核住院患者332例,在抗结核治疗前行支气管镜检查,收集支气管肺泡灌洗液（Bronchoalveolar lavage fluid,BALF）,行结核分枝杆菌涂片、BACTEC MGIT960快速培养及Xpert MTB/RIF检测,比较三种方法的阳性率,并分别以培养阳性及临床诊断为标准,计算Xpert MTB/RIF诊断涂阴肺结核的敏感度、特异度、阳性预测值、阴性预测值。结果 共有279例初治涂阴肺结核和53例非肺结核患者入组,279例初治涂阴肺结核的BALF检测结核分枝杆菌涂片、BACTEC MGIT960快速培养及Xpert MTB/RIF阳性率分别为2.51%、25.81%及50.90%,Xpert MTB/RIF阳性率明显高于涂片法及培养法,差异有统计学意义。以MGIT960培养阳性为标准,Xpert MTB/RIF诊断初治涂阴肺结核的敏感度为98.61%（71/72),特异度为100%（53/53）;阳性预测值为100.00%（71/71）,阴性预测值98.15%（53/54)。以临床诊断为标准,Xpert MTB/RIF诊断初治涂阴肺结核的敏感度为50.9%（142/279),特异度为100%（53/53）。阳性预测值为100%（142/142）,阴性预测值27.89%（53/190)。以DST 结果为金标准,Xpert MTB/RIF 检测利福平耐药的敏感度、特异度分别为 87.5％,98.44％,Xpert MTB/RIF与 DST两种方法检测利福平耐药的一致率达到 97.22％。且检测完成时间仅需2 h。结论 BALF中Xpert MTB/RIF检测敏感度、特异度均较高且能判断是否对利福平耐药,对初治涂阴肺结核有较大的早期快速诊断价值。     

Impact of introduction of xpert flu assay for influenza PCR testing on obstetric patients: a quality improvement project

Objective: The aim of this project was to assess the implementation of a quality improvement project regarding the introduction of on-site influenza PCR testing in a stand-alone obstetric hospital.

Methods: As part of a quality improvement project on the management of influenza in obstetric patients, the Xpert Flu assay (Cepheid Inc., Sunnyvale, CA) was introduced on-site and it replaced the previous method of PCR testing which was off-site. The main outcome measures were duration of antimicrobials, rate of admission and administration of oseltamavir in the emergency department.

Results: Twenty-eight patients were included in the pre-intervention period and 45 patients were included in the post-intervention period. Following the introduction of the test, there was a statistically significant reduction seen in commencement of antimicrobials (76% pre- and 33% post-intervention), and also rate of admission (88% pre- and 45% post-intervention) while there was a statistically significant improvement in the commencement of oseltamavir in the emergency department (72% pre-and 95% post-intervention) (p?Conclusion: Introduction of on-site rapid influenza PCR testing can lead to a significant improvement in patient management and should be considered for introduction to other sites.