First international external quality assessment scheme of nucleic acid amplification tests for the detection of Schistosoma and soil-transmitted helminths, including Strongyloides: A pilot study.
国际首个核酸扩增试验检测血吸虫和土传蠕虫 (包括圆线虫) 的外部质量评估方案: 一项试点研究。
- 作者列表："Cools P","van Lieshout L","Koelewijn R","Addiss D","Ajjampur SSR","Ayana M","Bradbury RS","Cantera JL","Dana D","Fischer K","Imtiaz R","Kabagenyi J","Lok J","McCarthy J","Mejia R","Mekonnen Z","Njenga SM","Othman N","Shao H","Traub R","Van Esbroeck M","Vercruysse J","Vlaminck J","Williams SA","Verweij JJ","van Hellemond JJ","Levecke B
BACKGROUND:Nucleic acid amplification tests (NAATs) are increasingly being used as diagnostic tools for soil-transmitted helminths (STHs; Ascaris lumbricoides, Trichuris trichiura, Necator americanus, Ancylostoma duodenale and A. ceylanicum), Strongyloides stercoralis and Schistosoma in human stool. Currently, there is a large diversity of NAATs being applied, but an external quality assessment scheme (EQAS) for these diagnostics is lacking. An EQAS involves a blinded process where test results reported by a laboratory are compared to those reported by reference or expert laboratories, allowing for an objective assessment of the diagnostic performance of a laboratory. In the current study, we piloted an international EQAS for these helminths (i) to investigate the feasibility of designing and delivering an EQAS; (ii) to assess the diagnostic performance of laboratories; and (iii) to gain insights into the different NAAT protocols used. METHODS AND PRINCIPAL FINDINGS:A panel of twelve stool samples and eight DNA samples was validated by six expert laboratories for the presence of six helminths (Ascaris, Trichuris, N. americanus, Ancylostoma, Strongyloides and Schistosoma). Subsequently this panel was sent to 15 globally dispersed laboratories. We found a high degree of diversity among the different DNA extraction and NAAT protocols. Although most laboratories performed well, we could clearly identify the laboratories that were poorly performing. CONCLUSIONS/SIGNIFICANCE:We showed the technical feasibility of an international EQAS for the NAAT of STHs, Strongyloides and Schistosoma. In addition, we documented that there are clear benefits for participating laboratories, as they can confirm and/or improve the diagnostic performance of their NAATs. Further research should aim to identify factors that explain poor performance of NAATs.
背景: 核酸扩增试验 (NAATs) 越来越多地被用作土壤传播的蠕虫 (STHs; 蛔虫，trichiura trichiura，Necator americanus，ancystoma十二指肠和A. ceylanicum)，人粪便中的圆线虫和血吸虫的诊断工具。目前，应用的naat种类繁多，但缺乏用于这些诊断的外部质量评估方案 (EQAS)。EQAS涉及盲法过程，其中将实验室报告的测试结果与参考或专家实验室报告的测试结果进行比较，从而允许客观评估实验室的诊断性能。在目前的研究中，我们对这些蠕虫试行了国际EQAS (i)，以研究设计和提供EQAS的可行性; (ii) 评估实验室的诊断性能; 以及 (iii) 深入了解使用的不同NAAT方案。 方法和主要发现: 一组由12个粪便样本和8个DNA样本组成的样本被6个专家实验室验证是否存在6种蠕虫 (蛔虫、鞭虫、美国奈瑟氏虫、钩虫、类圆线虫和血吸虫)。随后，该小组被派往15个全球分散的实验室。我们发现不同DNA提取和NAAT方案之间存在高度多样性。虽然大多数实验室表现良好，但我们可以清楚地识别出表现不佳的实验室。 结论/意义: 我们展示了STHs、圆线虫和血吸虫NAAT的国际方程的技术可行性。此外，我们记录了参与实验室有明显的好处，因为他们可以确认和/或改善他们的NAATs的诊断性能。进一步的研究应旨在确定解释NAATs表现不佳的因素。
METHODS::The cytologic evaluation of serous effusions may be challenging for a number of reasons. Distinction of benign, reactive conditions from malignancy represents the main focus when examining these specimens. The morphologic diagnosis of malignancy may be difficult due to the relative paucity of abnormal cells. In other situations, cellularity is not an issue, but the ability to confidently identify a second, foreign (i.e., tumor) population within a background mesothelial cells on the basis of cytomorphologic features alone may pose problems. Cases with definitive morphologic evidence of malignancy may require additional studies in order to determine the tumor subtype and, in the case of carcinoma, the primary site of origin. Cases in which a definitive and precise diagnosis of malignancy is made may be optimal candidates for further molecular testing in order to gain prognostic information and guide personal therapeutic decisions. Finally, while an inflammatory or infectious condition can be suggested on the basis of cellular components and associated background elements, the identification of causative agent(s) may be difficult without additional studies. In all of these situations, the use of ancillary studies and techniques is critical; their utility and appropriate application are the subject of this review.
METHODS:OBJECTIVE:To assess the rate of, and risk factors for, human cytomegalovirus viremia (HCMV) in donor+/recipient+ (HCMV serostatus matched) hematopoietic stem-cell transplantation (HSCT) recipients. METHODS:HCMV DNA from 144 donor+/recipient+ HSCT recipients was examined by quantitative polymerase chain reaction (qPCR). RESULTS:The cumulative incidence of HCMV viremia was 69.4% (100/144) during the 48 weeks after HSCT. In a multivariate analysis, acute graft-versus-host disease (aGVHD) was discovered to be a risk factor for the occurrence of HCMV viremia (P = .006). The cumulative incidence of HCMV viremia and increasing DNA loads were significantly associated with aGVHD occurrence (P = .001 for each). The occurrence of late-term HCMV viremia was associated with aGVHD (P = .001) and a higher DNA load during the first 12 weeks after HSCT (P = .04). CONCLUSIONS:aGVHD is a risk factor for HCMV viremia. Recipients with aGVHD who have a high HCMV DNA load should be strictly monitored to prevent HCMV activation.
METHODS:OBJECTIVES:Malaria is one of most common tropical diseases encountered in travellers and migrants. It requires an urgent and reliable diagnosis considering its potential severity. In this study, performance of five diagnostic assays were evaluated in a nonendemic region and compared prospectively to quantitative PCR (qPCR). METHODS:A prospective study was conducted at Toulouse Hospital from August 2017 to January 2018 and included all patients with initial Plasmodium screening. Thin and thick blood smears (TnS, TkS), quantitative buffy coat (QBC), rapid diagnostic tests (RDTs) and commercial loop-mediated isothermal amplification (LAMP) were independently performed on each blood sample and compared to our qPCR reference standard. RESULTS:The study encompassed 331 patients, mainly returning from Africa. qPCR detected 73 Plasmodium-positive samples (including 58 falciparum). Individually, LAMP had a 97.3% (71/73) sensitivity, far ahead of TnS (84.9%, 62/73), TkS (86.3%, 63/73), QBC (86.3%, 63/73) and RDT (86.3%, 63/73). RDT demonstrated a high sensitivity for falciparum (98.3%, 57/58) but missed all ovale, malariae and knowlesi infections. Specificity was excellent for all techniques (99.6-100%). The most sensitive diagnosis strategies were TnS + RDT (95.9%, 70/73), TnS + LAMP (97.3%, 71/73) and TnS + RDT + LAMP (100%, 73/73), about 10% higher than strategies using exclusively microscopy, TkS + TnS (87.7%, 64/73) or QBC + TnS (87.7%, 64/73). TnS remains necessary for Plasmodium species identification and quantification. Adding sequentially TnS only on LAMP-positive samples did not decrease TnS + LAMP strategy sensitivity. CONCLUSIONS:In nonendemic countries, the currently recommended microscopy-based strategies seem unsatisfactory for malaria diagnosis considering RDT and LAMP performance, two rapid and sensitive assays that require limited training.