Comparison of Microscopic Determination and Rapid Diagnostic Tests (RDTs) in the Detection of Plasmodium Infection

Malaria infection is the most common diagnosis made in Africa. Efficient diagnosis of malaria parasite is very vital for treatment of malaria infection. The efficacy of rapid diagnostic tests (RDTs) in comparison to microscopy, the gold standard, in the diagnosis of malaria in Nigeria has not been fully ascertained. This study compared the sensitivity, specificity and predictive values of RDTs available in Nigeria market with microscopy. Two RDT kits were used and their results were compared with the gold standard, microscopy using thick and thin blood films (TBF and tBF). TBF had sensitivity of 85%, specificity of 30%, positive predictive value (PPV) of 55.2%, and negative predictive value (NPV) of 66.6%;tBF had sensitivity of 80%, specificity of 35%, positive predictive value (PPV) of 55.2%, and negative predictive value (NPV) of 63.6%. Among the RDTs, Care Start HRP2 kit had sensitivity of 65%, specificity of 50%, positive predictive value (PPV) of 56.5%, and negative predictive value (NPV) of 59% while SD Bioline kit had sensitivity of 55%, specificity of 65%, PPV of 61%, and NPV of 59%. It can thus be inferred that rapid diagnostic test kits are not as sensitive as microscopy in diagnosis of malaria parasite, but they are more accurate and are thus suitable alternatives to microscopy.

Evaluation of a Rapid Diagnostic Test, Boson Biotech SARS CoV-2 Ag, for the Detection of SARS-CoV-2 in Gabon

1) Background: Rapid and acurate diagnostic testing for case identification, quarantine, and contact tracing is essential for managing the COVID 19 pandemic. Rapid antigen detection tests are available, however, it is important to evaluate their performances before use. We tested a rapid antigen detection of SARS-CoV-2, based on the immunochromatography (Boson Biotech SARS-CoV-2 Ag Test (Xiamen Boson Biotech Co., Ltd., China)) and the results were compared with the real time reverse transcriptase-Polymerase chain reaction (RT-PCR) (Gold standard) results;2) Methods: From November 2021 to December 2021, samples were collected from symptomatic patients and asymptomatic individuals referred for testing in a hospital during the second pandemic wave in Gabon. All these participants attending “CTA Angondjé”, a field hospital set up as part of the management of COVID-19 in Gabon. Two nasopharyngeal swabs were collected in all the patients, one for Ag test and the other for RT-PCR;3) Results: A total of 300 samples were collected from 189 symptomatic and 111 asymptomatic individuals. The sensitivity and specificity of the antigen test were 82.5% [95%CI 73.8 - 89.3] and 97.9 % [95%CI 92.2 - 98.2] respectively, and the diagnostic accuracy was 84.4% (95% CI: 79.8 - 88.3%). The antigen test was more likely to be positive for samples with RT-PCR Ct values ≤ 32, with a sensitivity of 89.8%;4) Conclusions: The Boson Biotech SARS-CoV-2 Ag Test has good sensitivity and can detect SARS-CoV-2 infection, especially among symptomatic individuals with low viral load. This test could be incorporated into efficient testing algorithms as an alternative to PCR to decrease diagnostic delays and curb viral transmission.

Secondary analysis of malaria rapid diagnostic tests from rounds 5–8 of WHO product testing with a focus on false-negative results

Despite the widespread use of malaria rapid diagnostic test(RDT)in clinical practice,there are a lot of challenges.We conducted a secondary analysis of 129 malaria RDT data from rounds 5–8 of the World Health Organization(WHO)product testing summary and discuss the causes of false-negative(FN)results with a focus on low parasite density,improper RDT storage,operation and interpretation,and Plasmodium falciparum with a pfhrp2/3 gene deletion.The results demonstrated that the malaria RDTs currently commercially available might cause FN results in practice.

Diagnosis of Malaria among Blood Donors in Port Harcourt, Nigeria: Microscopy or Rapid Diagnostic Tests?

The two most common techniques available for diagnosis of malaria in Nigeria are microscopy and rapid diagnostic tests (RDTs). However, in diagnosing asymptomatic Plasmodium parasitaemia among donors, the preferred technique should not only be timely but must not compromise diagnosis. It should be more sensitive with minimal chances of false negative results. This study was carried out to compare microscopy and RDTs as effective tools for diagnosis of Plasmodium parasitaemia among blood donors in Port Harcourt. There were 200 donors involved in the study among which 135 (67.5%) tested positive and 65 (32.5%) tested negative on microscopy whereas 30 (15.0%) tested positive and 170 (85.0%) tested negative to RDT with a statistically significant difference between both techniques. Data were analysed using the statistical package epi-info version 7.02. We therefore recommend that microscopy using giemsa-stained blood films remain the method of choice for diagnosis of Plasmodium parasitaemia among blood donors to prevent the spread of transfusion malaria.

Assessment of Rapid Diagnostic Tests Algorithms in Transfusion Medicine Setting

Background: The rapid diagnostic tests play a pivotal role in the screening of viral markers in blood qualification for transfusion in limited resource setting. Therefore, it is important to assess their analytical performances to ensure their proper functioning. Material and Methods: We performed a cross- sectional study by successive recruitment to assess the diagnostic value of rapid diagnostic tests algorithms using ELISA as a reference test. A total of 661 blood from donors were enrolled for this study. Rapid Diagnostic Tests (RDTs) and ELISA tests were performed for each sample by a couple of double-blinded biotechnologists. Data were collected on case report form and captured in Microsoft Excel then the file was imported and analyzed using R software version 4.0.3. Results: The diagnostic accuracy for the algorithms are summarized in Table 1. For HIV-algorithm, the internal validity parameters were as follow: sensitivity (sens) 99.0% (95% CI = 97.8, 99.5);specificity (spec) 98.3% (95% CI = 90.9, 99.7);positive likelihood ratio (PLR) 57.4 (95% CI = 8.2, 401.0);negative likelihood ratio (NLR) 0.01 (95% CI = 0.0005, 0.02);diagnostic odd ratio (DOR) 4710. HBV-Ag/Ab RDTs achieve the following diagnostic accuracy: sens 99.7% (95% CI = 98.3, 99.9);spec 98.8% (95% CI = 96.9, 95.5);PLR 81.8 (95% CI = 30.9, 217.0);NLR 0.003 (95% CI = 0.0004, 0.02);DOR 14,110. The analytical performances of HCV-Ab RDTs were as follow: sens 98.7% (95% CI = 97.5, 99.4);spec 93.1% (95% CI = 78.0, 98.1);PLR 14.3 (95% CI = 3.8, 54.5);NLR 1.5 (95% CI = 0.8, 2.8);DOR 962.6. The parameters evaluating the external validity of RDTs screening for the three viral markers when the theorical prevalence was < 5% are summarized in Figure 3. At the prevalence < 5%, the NPV of the three RDTs were 99.96%, 99.99% and 99.94%. At the same prevalence, we found the following Positive Predictive Values (PPV) 70.82%, 77.59% and 37.35% for HIV-Ag/Ab RDTs, HBV-Ag RDTs and HCV-Ab RDTs algorithms, respectively. The overall areas under the received operating characteristic (ROC) curves were 98.6%, 99.2% and 99.2%;95.9% for HIV-Ag/Ab RDTs, HBV-Ag RDTs and HCV-Ab RDTs algorithms, respectively. Conclusion: RDTs algorithms can play a pivotal role in the screening of HIV-Ab/Ag, HBs-Ag in the setting of resources limited-countries where financial and technical expertise shortages are a standard fare. However, their use for diagnostic purposes must be done with great caution and the result must necessarily be confirmed with an ELISA or molecular technique particularly for HCV-RDTs algorithm which achieved an NLR value > 0.1.

HIV-Viral Hepatitis C Coinfection or Cross-Reaction of Rapid Diagnostic Orientation Tests? About a Clinical Case Observed in Brazzaville in 2016

Coinfection with human immunodeficiency virus (HIV) and viral hepatitis is associated with high morbidity and mortality in the absence of clinical management, making identification of these cases crucial. Screening for hepatitis viral-HIV coinfection before initiation of treatment for viral hepatitis or HIV is recommended. In this context, we report a case of possible cross-reaction between the serology of viral hepatitis C and HIV infection by rapid diagnostic orientation tests. Although these rapid tests are the main diagnostic tools in developing countries, their scientific validation must be required before they are made available to practitioners. The knowledge and the rigorous application of diagnostic algorithms of viral infections will make it possible to save money and to better organize the prevention and management strategies for patients as part of an integrated Hepatitis/HIV program.

A comparative laboratory diagnosis of malaria:microscopy versus rapid diagnostic test kits

Objective:To compare the two methods of rapid diagnostic tests(RDTs)and microscopy in the diagnosis of malaria.Methods:RDTs and microscopy were carried out to diagnose malaria. Percentage malaria parasitaemia was calculated on thin films and all non-acute cases of plasmodiasis with less than 0.001%malaria parasitaemia were regarded as negative.Results were simply presented as percentage positive of the total number of patients under study.The results of RDTs were compared to those of microscopy while those of RDTs based on antigen were compared to those of RDTs based on antibody.Patients' follow-up was made for all cases.Results: All the 200 patients under present study tested positive to RDTs based on malaria antibodies(serum)method(100%).128 out of 200 tested positive to RDTs based on malaria antigen(whole blood)method(64%),while 118 out of 200 patients under present study tested positive to visual microscopy of Lieshman and diluted Giemsa(59%).All patients that tested positive to microscopy also tested positive to RDTs based on antigen.All patients on the second day of follow-up were non-febrile and had antimalaria drugs.Conclusions;We conclude based on the present study that the RDTs based on malaria antigen(whole blood)method is as specific as the traditional microscopy and even appears more sensitive than microscopy.The RDTs based on antibody(serum)method is unspecific thus it should not be encouraged.It is most likely that Africa being an endemic region,formation of certain levels of malaria antibody may not be uncommon.The present study also supports the opinion that a good number of febrile cases is not due to malaria. We support WHO's report on cost effectiveness of RDTs but,recommend that only the antigen based method should possibly,be adopted in Africa and other malaria endemic regions of the world.

Comparison of a rapid diagnostic test and microimmunofluorescence assay for detecting antibody to Orientia tsutsugamushi in scrub typhus patients in China

Objective:To evaluate the detection of IgM and IgG antibodies to Orientia tsutsugamushi(O. tsutsugamushi) by rapid diagnostic test(RDT) and microimmunofluorescence assay(ml FA). Methods:RDT using a mixture of recombinant 56-kDa proteins of O.tsutsugamushi and mIFA assay were performed on 20 patients from Fujian and 13 patients from Yunnan Province,and 82 sera samples from healthy farmers in Anhui Province and Beijing City in 2009.Comparison of the RDT and mIFA assay was performed by using X test and the P level of 【0.05 was considered to be significance.Results:Among these 82 normal sera samples,the specificity of RDT was 100%for both IgM and IgG tests.In 33 samples from patients with scrub typhus,5 cases were positively detected earlier by RDT than by mIFA in IgM test,and 2 cases were positive in IgG test.Sensitivities of RDT were 93.9%and 90.9%for IgM and IgG,respectively.The sensitivity of combination lest of IgM and IgG was 100%.Geometric mean titer diluted sera from confirmed cases by IFA and RDT assay were 1:37 vs.1:113(P【0.001) in IgM test and 1:99 vs.1:279 (P【0.05) in IgG test.Conclusions:RDT is more sensitivite than mIFA in the early diagnosis of scrub typhus and it is particularly applicable in rural areas.

Feasibility of Using Two versus Three Rapid Tests for HIV Diagnosis in India: Analysis of Public Health Program Data

Under India’s National AIDS Control Program (NACP), WHO recommended strategy of using three rapid tests is adopted for diagnosis of HIV in an asymptomatic individual. Since the NACP has a stringent kit evaluation procedure and due to the availability of newer third generation Rapid Diagnostic Tests (RDTs) it may be possible to adapt two test strategy for HIV diagnosis instead of the recommended three test strategy. The authors reviewed programmatic data on HIV testing to explore whether use of two rapid tests for HIV diagnosis as against three tests could be a feasible approach without compromising the quality and readability of testing. Data on the HIV diagnosis performed on serum specimens collected for the period of one year (2011-12) from 82 Integrated Testing and Counselling Centers (ICTCs) or Prevention of Parent to Child Transmission Centers (PPTCTs) associated with State reference Laboratories (SRLs) was analysed. Out of 654258 results that were analysed 25168 (3.84%) specimens were positives. It was observed that both two and three test algorithms provided similar results for majority (>99%) of the HIV positive specimens. Discordance was observed in labelling of specimen with inconclusive status (N = 21), however the true status of these samples could not be obtained. The analysis indicated that the use of two test algorithm will have programmatic benefits in terms of reduced financial burden to the programme and ease of procurement, shipment and storage before and after distribution without comprising the quality of the testing. The prospective study would confirm this observation.

Evaluation of Three Rapid Diagnostic Test Kits in the Diagnosis of <i>Plasmodium</i>Species Infections among Primary School Children in Baringo County, Kenya

Background: Due to the difficulty in implementing microscopy-based definitive diagnosis of malaria especially in resource-poor areas, rapid diagnostic test (RDT) kits as alternatives have been developed by different companies. Kits from different companies may differ in sensitivity and specificity. It is therefore imperative to conduct field evaluation of kits from different manufacturers before they are recommended for widespread use in diagnosis of malaria. The present study sought to evaluate the performance of malaria RDT kits from two manufacturers against microscopy in detection of Plasmodium spp. infections among primary school children in Baringo County, Kenya. Methods: Two cross-sectional comparative surveys to assess three RDT kits (CareStart HRP-2, SD Bioline Ag-Pf and SD Bioline Ag-Pf/Pan) were conducted on 561 pupils from three primary schools within the Kerio Valley of Baringo County, Kenya. Results: A total of 561 blood samples were tested for Plasmodium spp. within a period of four months. SD Bioline Ag-Pf/ Pan RDT kit had a higher sensitivity (90%) compared to that of CareStart HRP-2 (70%) but this was not statistically significant (McNemar’s χ2 = 0.5, df = 1, p = 0.4795). The sensitivity of SD Bioline Ag-Pf was the same as that of Care Start HRP-2 (82.4%). The number of positive samples by microscopy was relatively lower than those detected by RDT kits. Two cases of non-P. falciparum infections were detected by RDT kits during the second survey. Conclusion: The results of the present study suggest that the performance of the three kits in the diagnosis of P. falciparum infections was better than microscopy. The sensitivity of SD Bioline Ag-Pf/Pan was slightly greater than that of Care Start HRP-2, although not statistically different.

Comparison of Malaria Rapid Diagnostic Test Kit and Microscopy

Malaria is the most common single diagnosis made in many countries in Africa. Microscopy is the gold standard for laboratory diagnosis of malaria parasite, but it requires adequate training and the time to get results is longer than that for Rapid Diagnostic Tests (RDTs). Use of RDTs is an alternative diagnostic method. This method is quick and easy to carry out. This study examined 412 blood samples of patients who met the study inclusion criteria from the health centres. All of the samples obtained were tested by SD Bioline malaria Ag P.f test commonly available in Nigeria and parasite count was done from thick film prepared. The results obtained were presented as a proportion positive in comparison to the total number of participants enrolled. Of the 412 enrollees, 284 were tested positive with malaria using the RDT, 400 were tested positive with microscopy and 12 were negative using microscopy and RDT. This study confirms the superior sensitivity of microscopy to RDTs in diagnosis of malaria. Although RDTs are very useful for quick diagnosis of malaria, particularly in areas where access to the use of microscopy is not available, the possibility of a low performance by RDTs in malaria diagnosis should be emphasized on health practitioners and microcopy should be encouraged as much as possible.

Multiplex Rapid Test with Acceptable Diagnosis Performance as a Solution to Increase Diagnosis of Hepatitis B and C Viruses in Pregnant Women in an Area of High Prevalence of Both Hepatitis Viruses Associated with HIV

Background and Objective: HIV, hepatitis B virus (HBV) and hepatitis C virus (HCV) are very widespread in the world, however, less than 20% of the people affected are diagnosed and treated. This study aimed to determine the prevalence of HIV, HCV and HBV co-infections in pregnant women at Bangui Community University Hospital and the cost of screening. Methods: A cross-sectional study involving consenting pregnant women who came for antenatal care was performed. HIV, HCV antibodies and HBV antigens were detected using Exacto Triplex? HIV/HCV/HBsAg rapid test, cross-validated by ELISA tests. Sociodemographic and professional data, the modes of transmission and prevention of HIV and both hepatitis viruses were collected in a standard sheet and analyzed using the Epi-Info software version 7. Results: Pregnant women aged 15 to 24 were the most affected (45.3%);high school girls (46.0%), and pregnant women living in cohabitation (65.3%) were the most represented. Twenty-five (16.7%) worked in the formal sector, 12.7% were unemployed housewives and the remainder in the informal sector. The prevalence of HIV, HBV, and HCV viruses was 11.8%, 21.9% and 22.2%, respectively. The prevalence of co-infections was 8.6% for HIV-HBV, 10.2% for HIV-HCV, 14.7% for HBV-HCV and 6.5% for HIV-HBV-HCV. All positive results and 10% of negative results by the rapid test were confirmed by ELISA tests. The serology of the three viruses costs 39,000 FCFA (60 Euros) by ELISA compared to 10,000 FCFA (15.00 Euros) with Exacto Triplex? HIV/HCV/AgHBs (BioSynex, Strasbourg, France). Conclusion: The low level of education and awareness of hepatitis are barriers to development and indicate the importance of improving the literacy rate of women in the Central African Republic (CAR). Likewise, the high prevalence of the three viruses shows the need for the urgent establishment of a national program to combat viral hepatitis in the CAR.

Malaria rapid diagnostic tests in community pharmacies in Rwanda:availability,knowledge of community pharmacists,advantages,and disadvantages of licensing their use

Background Presumptive treatment of malaria is often practiced in community pharmacies across sub-Saharan Africa(SSA).To address this issue,the World Health Organization(WHO)recommends that malaria Rapid Diagnostic Tests(m-RDTs)be used in these settings,as they are used in the public sector.However,their use remains unlicensed in the community pharmacies in Rwanda.This can lessen their availability and foster presumptive treatment.Therefore,this study investigated the availability of m-RDTs,knowledge of community pharmacists on the use of m-RDTs,and explored Pharmacists’perceptions of the advantages and disadvantages of licensing the use of m-RDTs in community pharmacies.Methods This was a cross-sectional study among 200 licensed community pharmacists who were purposefully sampled nationwide from 11th February to 12th April 2022.Data was collected using an online data collection instrument composed of open-ended and closed-ended questions.Statistical analyses were performed using the Statistical Package for the Social Sciences(SPSS)version 25.0.The chi-square test was used to evaluate the association between the availability of m-RDTs and independent variables of interest.Content analysis was used for qualitative data.Results Although 59%were consulted by clients requesting to purchase m-RDTs,only 27%of the participants had m-RDTs in stock,66.5%had no training on the use of m-RDTs,and 18.5%were not at all familiar with using the m-RDTs.Most of the participants(91.5%)agreed that licensing the use of m-RDTs in community pharmacies could promote the rational use of antimalarials.The chi-square test indicated that being requested to sell m-RDTs(x^(2)=6.95,p=0.008),being requested to perform m-RDTs(x^(2)=5.39,p=0.02),familiarity using m-RDTs(x^(2)=17.24,p=0.002),availability of a nurse in the Pharmacy(x^(2)=11.68,p<0.001),and location of the pharmacy(x^(2)=9.13,p=0.048)were all significantly associated with the availability of m-RDTs in the pharmacy.Conclusions The availability of m-RDTs remains low in community pharmacies in Rwanda,and less training is provided to community pharmacists regarding the use of m-RDTs.Nevertheless,community pharmacists had positive perceptions of the advantages of licensing the use of m-RDTs.Thus,licensing the use of m-RDTs is believed to be the first step toward promoting the rational use of antimalarial medicines in Rwanda.

Evaluation of an Innovative Diagnostic Method for Detection of Antibodies and Antigens

Reports manifest a continuing need for the development of rapid and on-site (point of care) assays. Current diagnostic methods commonly used for detection of antibodies and antigens have significant limitations. Scientists at Micro Detect, Inc. have developed an innovative diagnostic device (method) that can be utilized broadly for antibody/antigen interactions including diagnostic assays in the medical, veterinary and food industries. The developed device can be utilized for the detection of antibodies against a single antigen or vice versa. It can also be tailored for specific panels that detect antigens or antibodies for diverse infectious agents, proteins, hormones, tumor markers, autoimmune markers, and allergens. Additionally, it can also be used for detection of toxins, antitoxins, nucleic acids, enzymes, drugs, etc. in both humans and animals. Specimens used in different formats of the device can be tears, saliva, whole blood, serum, plasma, urine, stool, and other bodily discharges. The good intra and inter precisions and acceptable linearity of the device support reliable use of the device. The CV of the device is 1.9% - 2.2%. Likewise, the performance of the device using 92 confirmed negative and positive specimens via a typical assay showed 100% sensitivity, 80% specificity, 96.8% efficacy, 80% positive predictive value, and 100% negative predictive value. The results of our feasibility study suggest reliable utility of a device for rapid, easy-to-use, inexpensive, and on-site (point of care) diagnostic assays. This presents a potential breakthrough in diagnostic methodologies that can be integrated into modern medicine and food industries.

Intraprocedural gastric juice analysis as compared to rapid urease test for real-time detection of Helicobacter pylori

BACKGROUND Endofaster is an innovative technology that can be combined with upper gastrointestinal endoscopy(UGE)to perform gastric juice analysis and real-time detection of Helicobacter pylori(H.pylori).AIM To assess the diagnostic performance of this technology and its impact on the management of H.pylori in the real-life clinical setting.METHODS Patients undergoing routine UGE were prospectively recruited.Biopsies were taken to assess gastric histology according to the updated Sydney system and for rapid urease test(RUT).Gastric juice sampling and analysis was performed using the Endofaster,and the diagnosis of H.pylori was based on real-time ammonium measurements.Histological detection of H.pylori served as the diagnostic gold standard for comparing Endofaster-based H.pylori diagnosis with RUT-based H.pylori detection.RESULTS A total of 198 patients were prospectively enrolled in an H.pylori diagnostic study by Endofasterbased gastric juice analysis(EGJA)during the UGE.Biopsies for RUT and histological assessment were performed on 161 patients(82 men and 79 women,mean age 54.8±19.2 years).H.pylori infection was detected by histology in 47(29.2%)patients.Overall,the sensitivity,specificity,accuracy,positive predictive value,and negative predictive value(NPV)for H.pylori diagnosis by EGJA were 91.5%,93.0%,92.6%,84.3%,and 96.4%,respectively.In patients on treatment with proton pump inhibitors,diagnostic sensitivity was reduced by 27.3%,while specificity and NPV were unaffected.EGJA and RUT were comparable in diagnostic performance and highly concordant in H.pylori detection(κ-value=0.85).CONCLUSION Endofaster allows for rapid and highly accurate detection of H.pylori during gastroscopy.This may guide taking additional biopsies for antibiotic susceptibility testing during the same procedure and then selecting an individually tailored eradication regimen.

Achieving Ultra-Low Detection Limit Using Nanofiber Labels for Rapid Disease Detection

Early diagnosis of diseases is critical in its effective management. Traditional disease detection methods require specialized equipment and trained personnel. With the introduction of rapid diagnostic test kits (RDTs), disease detection has become easier and faster. However, these RDTs have failed to compete with the specialized laboratory equipment due to their high detection limits and false alarm rates. This paper presents a novel method of using carbon nanofibers (CNFs) grown on glass microballoons (NMBs) to achieve ultra-low detection limits in RDTs. The NMBs have millions of nanosized CNFs grown on each microballoon, with each CNF having a strong bonding affinity for antibodies. The NMBs conjugated with secondary antibodies have therefore a significantly higher probability of capturing minute antigen concentrations in solution. Furthermore, the dark color formation at the capture zone makes visual disease detection possible. Human Immunoglobulin G (IgG) was selected as the model analyte to study the performance of NMBs using a sandwich immunoassay protocol. Ultra-low electrical detection limit of (4 pg/ml) and rapid re- sponse (~1 minute) was achieved using this method.

Protocol for a Diagnostic Accuracy Study of Polymerase Chain Reaction for Detecting Group B <i>Streptococcus</i>Colonisation in Early Labour or with Spontaneous Ruptured Membranes

Background: Group B Streptococcus [GBS] is a bacterium which transiently colonises the genital tract and can be transmitted from mother to baby at birth. Babies colonised with GBS can develop early-onset group B streptococcus disease [EOGBSD] which can lead to extended hospital stay, disability and death. One of the primary methods for determining which women are most likely to be GBS positive at the time of birth is antenatal universal culture-based screening. Recently Polymerase Chain Reaction [PCR] screening has emerged as a point-of-care method for screening women during the intrapartum period. This study will compare the diagnostic accuracy of this new technology and antenatal culture-based screening at 35 to 37 weeks gestational age, with the reference standard of formal culture-based testing in labour. Methods: This prospective observational study will take place in an Australian hospital. Consecutive women with one or more live fetuses, intending to have a vaginal birth will be asked to participate. Planned screening for GBS colonisation using microbiological culture on a self-collected specimen will occur at 35 to 37 completed weeks gestational age as per our usual hospital policy. A PCR GBS test by Xpert GBS (Cepheid) will be performed on admission to labour ward or at the time of rupture of membranes. The reference standard will be a formal GBS culture on a combined lower vaginal and perianal swab. The sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios will be estimated for both antenatal screening and the intrapartum Xpert GBS (Cepheid) point-of-care test and compared to the reference standard. Results: It is expected that the study will be completed by mid to late 2020. Conclusion: This study has the potential to improve the accuracy of GBS screening of pregnant women and therefore health outcomes for mothers and babies. There is also the potential for a cost savings to the health system.

Cost-effectiveness analysis of malaria rapid diagnostic tests:a systematic review

Background:Rapid diagnostic tests(RDT)can effectively manage malaria cases and reduce excess costs brought by misdiagnosis.However,few studies have evaluated the economic value of this technology.The purpose of this study is to systematically review the economic value of RDT in malaria diagnosis.Main text:A detailed search strategy was developed to identify published economic evaluations that provide evidence regarding the cost-effectiveness of malaria RDT.Electronic databases including MEDLINE,EMBASE,Biosis Previews,Web of Science and Cochrane Library were searched from Jan 2007 to July 2018.Two researchers screened studies independently based on pre-specified inclusion and exclusion criteria.The Consolidated Health Economic Evaluation Reporting Standards(CHEERS)checklist was applied to evaluate the quality of the studies.Then cost and effectiveness data were extracted and summarized in a narrative way.Fifteen economic evaluations of RDT compared to other diagnostic methods were identified.The overall quality of studies varied greatly but most of them were scored to be of high or moderate quality.Ten of the fifteen studies reported that RDT was likely to be a cost-effective approach compared to its comparisons,but the results could be influenced by the alternatives,study perspectives,malaria prevalence,and the types of RDT.Conclusions:Based on available evidence,RDT had the potential to be more cost-effective than either microscopy or presumptive diagnosis.Further research is also required to draw a more robust conclusion.

Evaluating the implementation of rapid diagnostic tests in a malaria elimination setting

Background It was recommended that malaria rapid diagnostic tests(RDTs)should be available in all epidemiological situations.But evidence was limited on the implementation of RDTs and its effectiveness in malaria elimination settings.This study examined the implementation of RDTs and how it affected the diagnosis of imported malaria patients in Jiangsu Province,China.Methods To scale up RDTs,this study developed an intervention package with four major elements covering the supply of RDT test,the training on RDTs,the monitoring and management of RDT use,and the advocacy of RDTs.By using a pretest-posttest control group design,we implemented the interventions in 4 cities in Jiangsu Province with the rest nine cities as controlled areas,from January 2017 to January 2018.Difference-in-Difference approach was used to evaluate the impact of the scale-up of RDTs on the identification of malaria cases.Three binary outcome measures were included to indicate delayed malaria diagnosis,malaria cases with confirmed malaria diagnosis at township-level institutions,and severe malaria cases,respectively.Linear probability regression was performed with time and group fixed effects and the interaction term between time and group.Results Intervention areas received sufficient RDT test supply,regular professional training programs,monthly tracking and management of RDT supply and use,and health education to targeted population.The implementation of interventions was associated with 10.8%(P=0.021)fewer patients with delayed diagnosis.But intervention areas did not see a higher likelihood of having confirmed diagnosis from township-level institutions(coefficient=-0.038,P=0.185)or reduced severe malaria cases(coef.=0.040,P=0.592).Conclusions The comprehensive package of RDT implementation in this study is promising in scaling up RDT use and improving access to care among malaria patients,especially in malaria elimination settings.

Performance of clinical signs and symptoms,rapid and reference laboratory diagnostic tests for diagnosis of human African trypanosomiasis by passive screening in Guinea:a prospective diagnostic accuracy study

Background Passive diagnosis of human African trypanosomiasis(HAT)at the health facility level is a major component of HAT control in Guinea.We examined which clinical signs and symptoms are associated with HAT,and assessed the performance of selected clinical presentations,of rapid diagnostic tests(RDT),and of reference laboratory tests on dried blood spots(DBS)for diagnosing HAT in Guinea.Method The study took place in 14 health facilities in Guinea,where 2345 clinical suspects were tested with RDTs(HAT Sero-K-Set,rHAT Sero-Strip,and SD Bioline HAT).Seropositives underwent parasitological examination(reference test)to confirm HAT and their DBS were tested in indirect enzyme-linked immunoassay(ELISA)/Trypanosoma brucei gambiense,trypanolysis,Loopamp Trypanosoma brucei Detection kit(LAMP)and m18S quantitative PCR(qPCR).Multivariable regression analysis assessed association of clinical presentation with HAT.Sensitivity,specificity,positive and negative predictive values of key clinical presentations,of the RDTs and of the DBS tests for HAT diagnosis were determined.Results The HAT prevalence,as confirmed parasitologically,was 2.0%(48/2345,95%CI:1.5–2.7%).Odds ratios(OR)for HAT were increased for participants with swollen lymph nodes(OR=96.7,95%CI:20.7–452.0),important weight loss(OR=20.4,95%CI:7.05–58.9),severe itching(OR=45.9,95%CI:7.3–288.7)or motor disorders(OR=4.5,95%CI:0.89–22.5).Presence of at least one of these clinical presentations was 75.6%(95%CI:73.8–77.4%)specific and 97.9%(95%CI:88.9–99.9%)sensitive for HAT.HAT Sero-K-Set,rHAT Sero-Strip,and SD Bioline HAT were respectively 97.5%(95%CI:96.8–98.1%),99.4%(95%CI:99.0–99.7%)and 97.9%(95%CI:97.2–98.4%)specific,and 100%(95%CI:92.5–100.0%),59.6%(95%CI:44.3–73.3%)and 93.8%(95%CI:82.8–98.7%)sensitive for HAT.The RDT’s positive and negative predictive values ranged from 45.2–66.7%and 99.2–100%respectively.All DBS tests had specificities≥92.9%.While LAMP and m18S qPCR sensitivities were below 50%,trypanolysis and ELISA/T.b.gambiense had sensitivities of 85.3%(95%CI:68.9–95.0%)and 67.6%(95%CI:49.5–82.6%).Conclusions Presence of swollen lymph nodes,important weight loss,severe itching or motor disorders are simple but accurate clinical criteria for HAT referral in HAT endemic areas in Guinea.Diagnostic performances of HAT Sero-K-Set and SD Bioline HAT are sufficient for referring positives to microscopy.Trypanolysis on DBS may discriminate HAT patients from false RDT positives.