We aimed to assess the performance of Ag-RDT and RT-qPCR with regard to detecting infectious SARS-CoV-2 in cell cultures, as their diagnostic test accuracy (DTA) compared to virus isolation remains largely unknown. We searched three databases up to 15 December 2021 for DTA studies. The bivariate model was used to synthesise the estimates. Risk of bias was assessed using QUADAS-2/C. Twenty studies (2605 respiratory samples) using cell culture and at least one molecular test were identified. All studies were at high or unclear risk of bias in at least one domain. Three comparative DTA studies reported results on Ag-RDT and RT-qPCR against cell culture. Two studies evaluated RT-qPCR against cell culture only. Fifteen studies evaluated Ag-RDT against cell culture as reference standard in RT-qPCR-positive samples. For Ag-RDT, summary sensitivity was 93% (95% CI 78; 98%) and specificity 87% (95% CI 70; 95%). For RT-qPCR, summary sensitivity (continuity-corrected) was 98% (95% CI 95; 99%) and specificity 45% (95% CI 28; 63%). In studies relying on RT-qPCR-positive subsamples (n = 15), the summary sensitivity of Ag-RDT was 93% (95% CI 92; 93%) and specificity 63% (95% CI 63; 63%). Ag-RDT show moderately high sensitivity, detecting most but not all samples demonstrated to be infectious based on virus isolation. Although RT-qPCR exhibits high sensitivity across studies, its low specificity to indicate infectivity raises the question of its general superiority in all clinical settings. Study findings should be interpreted with caution due to the risk of bias, heterogeneity and the imperfect reference standard for infectivity.

The global malaria epidemic is still severe. Because of simple procedures, rapid detection and accuracy results, rapid diagnostic test (RDT) has become the most important and the most widely used diagnostic tool for malaria prevention and control. However, deletions in the RDT target Plasmodium falciparum histidine-rich protein 2/3 (Pfhrp2/3) genes may cause false-negative results of RDT, which has been included as one of the four biological threats to global malaria elimination. This article reviews the applications of RDT in the global malaria diagnosis, analyzes the threats and challenges caused by Pfhrp2/3 gene deletion, proposes methods for monitoring Pfhrp2/3 gene deletion, and summarizes the causes and countermeasures of negative RDT detections, so as to provide insights into consolidation of malaria elimination achievements in China and contributions to global malaria elimination.
［摘要］ 全球疟疾流行依然严峻, 疟疾快速诊断试纸条 (rapid diagnostic test, RDT) 操作简便、检测快速、结果准确, 已成为当前疟 疾防控中最重要和最广泛使用的诊断工具。但RDT靶标恶性疟 原虫富组氨酸蛋白2/3 (Plasmodium falciparum histidine-rich protein 2/3, Pfhrp2/3) 基因缺失可导致RDT产生假阴性检测结果, 被 WHO列为全球消除疟疾的四大生物学挑战之一。本文通过回顾 RDT在全球疟疾诊断中的应用, 分析Pfhrp2/3 基因缺失带来的威 胁与挑战、提出Pfhrp2/3 基因缺失的监测方法、总结RDT检测阴性 的原因与对策, 为巩固我国消除疟疾成果、助力全球消除疟疾提 供参考。.

BACKGROUND: In Equatorial Guinea, only 54 % of people living with HIV know their HIV status. There are no confirmatory or molecular diagnostic techniques for early diagnosis or monitoring of infection in the country. Rapid diagnostic tests can induce false-positive diagnoses if used as a confirmatory technique. Our study aimed to identify the challenges of early HIV diagnosis in Equatorial Guinea by analyzing the rate of false positive diagnoses, diagnostic and therapeutic delays, and treatment failures among those on antiretroviral therapy.
METHODS: From 2019-2022, dried blood from 341 children, adolescents and adults diagnosed in Equatorial Guinea as HIV-positive by rapid diagnostic testing, and from 54 HIV-exposed infants were collected in Bata and sent to Madrid to confirm HIV-infection by molecular (Xpert HIV-1Qual, Cepheid) and/or serological confirmatory assays (Geenius-HIV-1/2, BioRad). HIV diagnostic delay (CD4 <350cells/mm3), advanced disease at diagnosis (CD4 <200cells/mm3) and antiretroviral treatment delay and failure (viraemia >1,000RNA-HIV-1-copies/ml) were also studied after viral quantification (XpertVL HIV-1, Cepheid).
RESULTS: False-positive diagnoses were identified in 5 % of analysed samples. HIV infection was confirmed in 90.5 % of previously diagnosed patients in Equatorial Guinea and 3.7 % of HIV-exposed children undiagnosed in the field. Two-thirds of each new HIV patient had delayed diagnosis, and one-third had advanced disease. Treatment delay occurred in 28.3 % of patients, being around four times more likely in adolescents/adults than children. More than half (56 %) of 232 treated patients presented treatment failure, being significantly higher in children/adolescents than in adults (82.9 %/90 % vs. 45.6 %, p < 0.001).
CONCLUSIONS: We identified some challenges of early HIV diagnosis in Equatorial Guinea, revealing a high rate of false positive diagnoses, diagnostic/treatment delays, and treatment failures that need to be addressed. The implementation of more accurate rapid diagnostic techniques and confirmatory tests, along with improving access to care, treatment, awareness, and screening, would contribute to controlling the spread of HIV in the country.

BACKGROUND: Southern African countries have the largest global burden of HIV and syphilis, with a high prevalence among women of reproductive age. Although antenatal screening is standard of care, syphilis screening has generally lagged behind HIV screening. We aimed to evaluate the performance and operational characteristics of two commercial dual HIV/syphilis point-of-care tests (POCTs) for simultaneous maternal HIV/syphilis screening.
METHODS: A clinic-based evaluation of dual HIV/syphilis POCTs (SD Bioline and Chembio) was conducted at five primary healthcare centres (PHCs) in South Africa and Zambia. POCT results using capillary fingerprick blood were compared to reference laboratory syphilis and HIV serological assays.
RESULTS: Three thousand four hundred twelve consenting pregnant women aged ≥ 18 years were enrolled. The prevalence of treponemal antibody seropositivity and HIV infection ranged from 3.7 to 9.9% (n = 253) and 17.8 to 21.3% (n = 643), respectively. Pooled sensitivity for syphilis compared to the reference assay was 66.0% (95%CI 57.7-73.4) with SD Bioline and 67.9% (95%CI 58.2-76.3) with Chembio. Pooled specificity for syphilis was above 98% with both POCTs. The sensitivities of SD Bioline and Chembio assays were 78.0% (95%CI 68.6-85.7) and 81.0% (95%CI 71.9-88.2), respectively compared to an active syphilis case definition of treponemal test positive with a rapid plasma reagin titre of ≥ 8. The negative predictive values (NPVs) based on various prevalence estimates for syphilis with both assays ranged from 97 to 99%. The pooled sensitivity for HIV was 92.1% (95%CI 89.4-94.2) with SD Bioline; and 91.5% (95%CI 88.2-93.9) with Chembio. The pooled specificities for HIV were 97.2% (95%CI 94.8-98.5) with SD Bioline and 96.7% (95%CI 95.1-97.8) with Chembio. The NPV based on various prevalence estimates for HIV with both assays was approximately 98%. Most participating women (91%) preferred dual POCTs over two single POCTs for HIV and syphilis, and healthcare providers gave favourable feedback on the utility of both assays at PHC level.
CONCLUSIONS: Based on the need to improve antenatal screening coverage for syphilis, dual HIV/syphilis POCTs could be effectively incorporated into antenatal testing algorithms to enhance efforts towards elimination of mother-to-child transmission of these infections.

UNASSIGNED: The objective of this study was to develop a rapid and accurate clustered regularly interspaced short palindromic repeats (CRISPR)/Cas12a-based molecular diagnostic assay (Rapid Identification of Mycoses using CRISPR, RID-MyC assay) to detect fungal nucleic acids and to compare it with existing conventional mycologic methods for the diagnosis of fungal keratitis (FK).
UNASSIGNED: This study was structured as a development and validation study focusing on the creation and assessment of the RID-MyC assay as a novel diagnostic modality for FK.
UNASSIGNED: Participants comprised 142 individuals presenting with suspected microbial keratitis at 3 tertiary care institutions in South India.
UNASSIGNED: The RID-MyC assay utilized recombinase polymerase amplification targeting the 18S ribosomal RNA gene for isothermal amplification, followed by a CRISPR/Cas12a reaction. This was benchmarked against microscopy, culture, and polymerase chain reaction for the diagnosis of FK.
UNASSIGNED: The primary outcome measures focused on the analytical sensitivity and specificity of the RID-MyC assay in detecting fungal nucleic acids. Secondary outcomes measured the assay\'s diagnostic sensitivity and specificity for FK, including its concordance with conventional diagnostic methods.
UNASSIGNED: The RID-MyC assay exhibited a detection limit ranging from 13.3 to 16.6 genomic copies across 4 common fungal species. In patients with microbial keratitis, the RID-MyC assay showed substantial agreement with microscopy (kappa = 0.714) and fair agreement with culture (kappa = 0.399). The assay demonstrated a sensitivity of 93.27% (95% confidence interval [CI], 86.62%-97.25%) and a specificity of 89.47% (95% CI, 66.86%-98.70%) for FK diagnosis, with a median diagnostic time of 50 minutes (range, 35-124 minutes).
UNASSIGNED: The RID-MyC assay, utilizing CRISPR-Cas12a technology, offers high diagnostic accuracy for FK. Its potential for point-of-care use could expedite and enhance the precision of fungal diagnostics, presenting a promising solution to current diagnostic challenges.
UNASSIGNED: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

BACKGROUND: The recommendation of universal diagnostic testing before malaria treatment aimed to address the problem of over-treatment with artemisinin-based combination therapy and the heightened risk of selection pressure and drug resistance and the use of malaria rapid diagnostic test (MRDT) was a key strategy, particularly among primary healthcare (PHC) workers whose access to and use of other forms of diagnostic testing were virtually absent. However, the use of MRDT can only remedy over-treatment when health workers respond appropriately to negative MRDT results by not prescribing anti-malarial drugs. This study assessed the use of MRDT and anti-malarial drug prescription practices, and the predictors, among PHC workers in Ebonyi state, Nigeria.
METHODS: We conducted an analytical cross-sectional questionnaire survey, among consenting PHC workers involved in the diagnosis and treatment of malaria, from January 15, 2020 to February 5, 2020. Data was collected via structured self-administered questionnaire and analysed using descriptive statistics and bivariate and multivariate generalized estimating equations.
RESULTS: Of the 490 participants surveyed: 81.4% usually/routinely used MRDT for malaria diagnosis and 18.6% usually used only clinical symptoms; 78.0% used MRDT for malaria diagnosis for all/most of their patients suspected of having malaria in the preceding month while 22.0% used MRDT for none/few/some; 74.9% had good anti-malarial drug prescription practice; and 68.0% reported appropriate response to negative MRDT results (never/rarely prescribed anti-malarial drugs for the patients) while 32.0% reported inappropriate response (sometimes/often/always prescribed anti-malarial drugs). The identified predictor(s): of the use of MRDT was working in health facilities supported by the United States\' President\'s Malaria Initiative (PMI-supported health facilities); of good anti-malarial drug prescription practice were having good opinion about MRDT, having good knowledge about malaria diagnosis and MRDT, being a health attendant, working in PMI-supported health facilities, and increase in age; and of appropriate response to negative MRDT results was having good opinion about MRDT.
CONCLUSIONS: The evidence indicate the need for, and highlight factors to be considered by, further policy actions and interventions for optimal use of MRDT and anti-malarial drug prescription practices among the PHC workers in Ebonyi state, Nigeria, and similar settings.

Rapid syphilis testing plays a crucial role in global health strategies, addressing the urgent need for prompt and accurate diagnostics, especially in settings with limited resources. Despite their practical utility, these tests often lack thorough validation, leading to concerns about their efficacy and reliability. This study aims to evaluate two prototypes of the Onsite Syphilis Ab Combo Rapid Test (Fd and Ff) and compare their performance with the established chemiluminescent microparticle immunoassay (CMIA) method. Employing a reverse algorithm approach, the study analyzed 450 serum samples, including those from syphilis patients, healthy individuals, and cases with potential cross-reactions. Results of the rapid test kit were then correlated with CMIA findings, RPR, and TPPA titers. The results showed that prototype Fd exhibited a sensitivity of 100.0%, specificity of 98.8%, positive predictive value (PPV) of 8.4%, negative predictive value (NPV) of 100.00% and accuracy of 98.8%. Similarly, prototype Ff exhibited sensitivity of 100.0%, but with a slightly higher specificity of 99.6%, PPV of 21.5%, NPV of 100.0% and accuracy of 99.6%. Moreover, both prototypes Fd and Ff of the Onsite Syphilis Ab Combo Rapid Test demonstrated significant efficacy diagnostic tool, offering clear and straightforward interpretation for clinicians in varied CMIA, RPR and TPPA titer scenarios. The Onsite Syphilis Ab Combo Rapid Test prototypes, Fd and Ff, demonstrated high sensitivity and specificity, comparable to CMIA methods. The effectiveness highlights their suitability for syphilis screening, particularly in non-laboratory settings or situations requiring immediate results. The validation of these prototypes supports their integration into current syphilis diagnostic algorithms, potentially contributing to improved public health outcomes.

OBJECTIVE: Globally, there are estimated to be 2.9 million cholera cases annually. Early detection of cholera outbreaks is crucial for resource allocation for case management and for targeted interventions to be delivered to stop the spread of cholera. In resource limited settings such as Eastern Democratic Republic of the Congo (DRC), there is often limited laboratory capacity for analysing stool samples for cholera by bacterial culture. Therefore, rapid diagnostic tests (RDTs) for cholera present a promising tool to rapidly test stool samples in a health facility setting for cholera. Our objective is to evaluate the Crystal VC O1 RDT for cholera detection compared with bacterial culture and polymerase chain reaction (PCR) for Vibrio cholerae.
METHODS: From March 2020 to December 2022, stool samples were collected from 644 diarrhoea patients admitted to 94 health facilities in Bukavu in Eastern DRC. Patient stool samples were analysed by Crystal VC O1 RDT for cholera and by bacterial culture and PCR for V. cholerae O1.
RESULTS: Twenty six percent of diarrhoea patients (166/644) had stool samples positive for cholera by RDT, and 24% (152/644) had stool samples positive for V. cholerae O1 by bacterial culture or PCR. The overall specificity and sensitivity of the Crystal VC O1 RDT by direct testing was 94% (95% confidence interval [CI]: 92%-96%) and 90% (95% CI, 84%-94%), respectively, when compared with either a positive result by bacterial culture or PCR.
CONCLUSIONS: Our findings suggest that the Crystal VC O1 RDT presents a promising tool for cholera surveillance in this cholera endemic setting in sub-Saharan Africa.

Hepatitis C virus core antigen (HCVcAg) testing can simplify and decrease costs of HCV infection confirmation compared to molecular testing (nucleic acid testing). We piloted HCVcAg testing for the confirmation of active infection. The study was conducted during June through December 2022 among the police and the general population of Islamabad, Pakistan age 18 years and older. Initial screening for HCV antibody was conducted using a rapid diagnostic test (RDT) for all consenting participants. Those who tested positive had venous blood samples tested for HCVcAg, platelets and aspartate aminotransferase (AST). Persons with HCVcAg values ≥3 fmol/L were defined as viremic, and they were offered treatment with direct acting antiviral (DAA) medications, sofosbuvir and daclatasvir. Aspartate aminotransferase to platelet ratio index (APRI) was calculated for each HCV infected person, and those with an APRI score <1.5 received treatment for 12 weeks, while those with APRI ≥ to 1.5 received 24 weeks of treatment. A total of 15,628 persons were screened for anti-HCV using RDT and 643 (4.1%) tested positive. HCVcAg values of ≥3 fmol/L was found in 399/643 (62.1%), and all were offered and accepted treatment. Of those treated, 273/399 (68.4%) returned for a follow-up SVR and HCVcAg was not detected in 261/273, a 95.6% cure rate. The pilot study demonstrated the effectiveness of reaching and treating an urban population using RDT for screening and HCVcAg for confirmation of infection and test of cure.

UNASSIGNED: Viral infection is responsible for the majority of respiratory tract infections (RTI). This retrospective study evaluates the advantages of using the multiplex Xpert Xpress CoV-2/Flu/RSV plus kit in laboratory diagnosis of RTI caused by the most related viruses.
UNASSIGNED: Data were obtained from medical records between November 2021 and May 2023 for any sample tested using either the Xpert Xpress Flu/RSV kit, Xpert Xpress Flu kit, Xpert Xpress SARS-CoV-2 kit, and Xpert Xpress CoV-2/Flu/RSV plus kit.
UNASSIGNED: Influenza virus A was detected in 8.5% (55/649) of the samples using the Flu PCR kit and in 4.9% (123/2538) using CoV-2/Flu/RSV plus kit, while influenza virus B detection rates were 3.7% (24/649) using the Flu PCR kit and 1.7% (43/2538) using the CoV-2/Flu/RSV plus kit. However, the detection rates using the two kits were comparable when evaluated for the same time period of the year. SARS-CoV-2 infections were detected in 16.9% (1545/9153) and 10.5% (266/2538) of the cases using the SARS-CoV-2 kit and CoV-2/Flu/RSV plus kits, respectively. Respiratory syncytial virus (RSV) was identified in 17.7% (66/372) of children using Flu/RSV kit; this number dropped significantly when age-targeted testing of RSV was performed due to involvements of adults. With the CoV-2/Flu/RSV plus kit, about 34% (35/103) of RSV infections detected were in patients aged >20 years; these cases would have previously been overlooked because adults are not routinely tested for RSV using the Flu/RSV kit. All coinfection cases (n = 16) were only detected with the CoV-2/Flu/RSV plus kit.
UNASSIGNED: The use of Xpert Xpress CoV-2/Flu/RSV plus kit not only results in shorter turnaround times through accurate detection of all four viruses, but also provides information on RSV infection in adults and coinfection rates.