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347 result(s) for "RDTs"
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Comparison of three diagnostic methods (microscopy, RDT, and PCR) for the detection of malaria parasites in representative samples from Equatorial Guinea
Background Malaria in Equatorial Guinea remains a major public health problem. The country is a holo-endemic area with a year-round transmission pattern. In 2016, the prevalence of malaria was 12.09% and malaria caused 15% of deaths among children under 5 years. In the Continental Region, 95.2% of malaria infections were Plasmodium falciparum , 9.5% Plasmodium vivax , and eight cases mixed infection in 2011. The main strategy for malaria control is quick and accurate diagnosis followed by effective treatment. Early and accurate diagnosis of malaria is essential for both effective disease management and malaria surveillance. The quality of malaria diagnosis is important in all settings, as misdiagnosis can result in significant morbidity and mortality. Microscopy and RDTs are the primary choices for diagnosing malaria in the field. However, false-negative results may delay treatment and increase the number of persons capable of infecting mosquitoes in the community. The present study analysed the performance of microscopy and RDTs, the two main techniques used in Equatorial Guinea for the diagnosis of malaria, compared to semi-nested multiplex PCR (SnM-PCR). Results A total of 1724 samples tested by microscopy, RDT, and SnM-PCR were analysed. Among the negative samples detected by microscopy, 335 (19.4%) were false negatives. On the other hand, the negative samples detected by RDT, 128 (13.3%) were false negatives based on PCR. This finding is important, especially since it is a group of patients who did not receive antimalarial treatment. Conclusions Owing to the high number of false negatives in microscopy, it is necessary to reinforce training in microscopy, the “Gold Standard” in endemic areas. A network of reference centres could potentially support ongoing diagnostic and control efforts made by malaria control programmes in the long term, as the National Centre of Tropical Medicine currently supports the National Programme against Malaria of Equatorial Guinea to perform all of the molecular studies necessary for disease control. Taking into account the results obtained with the RDTs, an exhaustive study of the deletion of the hrp2 gene must be done in EG to help choose the correct RDT for this area.
Price, quality, and market dynamics of malaria rapid diagnostic tests: analysis of Global Fund 2009–2018 data
Background Rapid diagnostic tests (RDTs) for malaria are a vital part of global malaria control. Over the past decade, RDT prices have declined, and quality has improved. However, the relationship between price and product quality and their larger implications on the market have yet to be characterized. This analysis used purchase data from the Global Fund together with product quality data from the World Health Organization (WHO) and Foundation for Innovative New Diagnostics (FIND) Malaria RDT Product Testing Programme to understand three unanswered questions: (1) Has the market share by quality of RDTs in the Global Fund’s procurement orders changed over time? (2) What is the relationship between unit price and RDT quality? (3) Has the market for RDTs financed by the Global Fund become more concentrated over time? Methods Data from 10,075 procurement transactions in the Global Fund’s database, which includes year, product, volume, and price, was merged with product quality data from all eight rounds of the WHO-FIND programme, which evaluated 227 unique RDT products. To describe trends in market share by quality level of RDT, descriptive statistics were used to analyse trends in market share from 2009 to 2018. A generalized linear regression model was then applied to characterize the relationship between price and panel detection score (PDS), adjusting for order volume, year purchased, product type, and manufacturer. Third, a Herfindahl–Hirschman Index (HHI) score was calculated to characterize the degree of market concentration. Results Lower-quality RDTs have lost market share between 2009 and 2018, as have the highest-quality RDTs. No statistically significant relationship between price per test and PDS was found when adjusting for order volume, product type, and year of purchase. The HHI was 3,570, indicating a highly concentrated market. Conclusions Advancements in RDT affordability, quality, and access over the past decade risk stagnation if health of the RDT market as a whole is neglected. These results suggest that from 2009 to 2018, this market was highly concentrated and that quality was not a distinguishing feature between RDTs. This information adds to previous reports noting concerns about the long-term sustainability of this market. Further research is needed to understand the causes and implications of these trends.
Evaluation of NxTek™ Eliminate Malaria-PF test and biocredit rapid diagnostic tests for detecting Plasmodium species in Southern Ethiopia
Background Rapid diagnostic tests (RDTs) play an essential role in the prompt diagnosis of malaria in settings where using microscopy is not feasible. This study aimed to evaluate the diagnostic performance of NxTek™ Eliminate Malaria- Pf test, Biocredit RDTs Pf(pLDH/HRP2) and Pf/Pv(pLDH/pLDH) for the detection of Plasmodium species. Methods A health facility-based cross-sectional study was conducted from September to November 2024 in 384 malaria-suspected febrile study subjects at Dilla Zuria health facility. Venous blood samples were collected for malaria diagnosis using microscopy, RDTs, and quantitative Polymerase Chain Reaction (qPCR). Sensitivity, specificity, positive/negative predictive value, and accuracy were calculated using microscopy and qPCR as reference standards. Results Using microscopy as the reference standard, the NxTek™ Eliminate Malaria-Pf test demonstrated a sensitivity of 87.6% and a specificity of 91.3% for the detection of P. falciparum. The Biocredit Pf/Pv (pLDH/pLDH) RDT exhibited a sensitivity of 97.9% and specificity of 97.4% for P. falciparum , and a sensitivity of 94.5% and specificity of 97.5% for P. vivax . The Biocredit Pf (pLDH/HRP2) RDT showed sensitivity and specificity values of 97.4% and 97.5%, respectively. In comparison, the SD Bioline RDT yielded a sensitivity of 51.3% and specificity of 93.2% for P. falciparum , and sensitivity and specificity of 86.3% and 96.5%, respectively, for P. vivax . When using quantitative PCR (qPCR) as the reference standard, the Biocredit Pf/Pv (pLDH/pLDH) RDT demonstrated a sensitivity of 95.5% and specificity of 96.4% for P. falciparum , and sensitivity and specificity of 90.8% and 99.1%, respectively, for P. vivax . Conclusion The Biocredit RDTs outperformed conventional RDTs in both sensitivity and specificity and met the World Health Organization’s (WHO) diagnostic criteria. These results support their utility in routine malaria diagnosis, particularly in resource-limited endemic settings.
Board Attributes, Corporate Social Responsibility Strategy, and Corporate Environmental and Social Performance
In this paper, we draw on insights from theories in the management and corporate governance literature to develop a theoretical model that makes explicit the links between a firm's corporate social responsibility (CSR) related board attributes, its board CSR strategy, and its environmental and social performance. We then test the model using structural equation modeling approach. We find that the greater the CSR orientation of the board (as measured by the board's independence, gender diversity, and financial expertise on audit committee), the more proactive and comprehensive the firm's CSR strategy, and the higher its environmental and social performance. Moreover, we find this link to be endogenous and self-reinforcing, with superior CSR performers tending to further strengthen their board CSR orientation. This result while positive is also suggestive of the widening of the gap between the leads and laggards in CSR. Therefore, the question arises as to how 'leaders' are using their superior CSR competencies seen by many scholars as a source of corporate (at times unfair) competitive advantage. Stakeholders of corporations therefore need to be cognizant of this aspect of CSR when evaluating a firm's CSR activities. Policy makers also need to be cognizant of these concerns when designing regulation in this field.
First evidence of the deletion in the pfhrp2 and pfhrp3 genes in Plasmodium falciparum from Equatorial Guinea
Background The World Health Organization (WHO) recommends rapid diagnostic tests (RDTs) as a good alternative malaria-diagnosis method in remote parts of sub-Saharan Africa. The majority of commercial RDTs currently available detect the Plasmodium falciparum protein histidine-rich protein 2 (PfHRP2). There have also been recent reports of pfhrp2 gene deletions being found in parasites collected from several African countries. The WHO has concluded that lacking the pfhrp2 gene must be monitored in Africa. The purpose of the study was to analyse why the samples that were positive by PCR were negative by RDTs and, therefore, to determine whether there have been deletions in the pfhrp2 and/or pfhrp3 genes. Methods Malaria NM-PCR was carried out on all the samples collected in the field. A group of 128 samples was positive by PCR but negative by RDT; these samples were classified as RDT false-negatives. PCR was carried out for exon2 of pfhrp2 and pfhrp3 genes to detect the presence or absence of these two genes. Frequencies with 95% confidence intervals (CIs) were used for prevalence estimates. Associations were assessed by the Chi square test or Fisher´s exact test. The level of significance was set at p ≤ 0.05. Statistical analyses were performed using the software package SPSSv.15.0. Results After PCR, 81 samples were identified (4.7%, 95% CI 3.8–5.8) which had deletion in both genes, pfhrp2 and pfhrp3 . Overall, however, 11 samples (0.6%, 95% CI 0.36–1.14) had deletion only in pfhrp2 but not in pfhrp3 , and 15 (0.9%, 95% CI 0.6–1.5) presented with deletion only in pfhrp3 but not in pfhrp2 . Considering the pfhrp2 gene separately, within the total of 1724 samples, 92 (5.3%, 95% CI 4.37–6.5) had evidence of deletion. Conclusion The present study provides the first evidence of deletion in the pfhrp2 and pfhrp3 genes in P. falciparum isolates from Equatorial Guinea. However, larger studies across different regions within the country and across different seasonal profiles are needed to determine the full extent of pfhrp2 and pfhrp3 deletion. It is strongly recommended to implement an active surveillance programme in order to detect any increases in pfhrp2 and pfhrp3 deletion frequencies.
Accuracy of recording and reporting of malaria rapid diagnostic tests in Nigeria
Background Malaria remains a major health concern in Nigeria. Rapid diagnostic tests (RDTs) are widely used in health facilities to confirm malaria before treatment. However, concerns remain about healthcare workers (HCWs) adherence to, and reporting of test results. This study assessed the accuracy of RDT results recorded in health facility registers in two states of Nigeria by comparing them with an unbiased reference standard and explored factors influencing interrater agreement. Methods A mixed-method evaluation was conducted in 16 health facilities across Oyo and Sokoto States. RDTs performed by HCWs were photographed using a digital RDT reader and independently re-interpreted by a trained, independent, objective panel. Surveys of health facilities and HCWs collected data on factors that could influence RDT recording. Interrater agreement between RDT results recorded by HCWs in facility registers and the external panel was assessed using Cohen’s kappa. A meta-analytical approach was used to calculate a pooled summary kappa value across facilities, and potential moderators of agreement were examined, including characteristics of facilities, HCWs and RDTs. Results Out of 19,586 RDTs captured, 18,319 were included in the analysis. Overall, 6.2% of RDTs were misrecorded as positive and 3.7% as negative in health facility registers, yielding a positive predictive value of 87.2% (95% confidence interval [CI] 86.4%, 87.8%) and negative predictive value of 92.9%. The overall percentage agreement was 90.2% (95% CI 89.7%, 90.6%), and the pooled kappa statistic was 0.80 (95% CI 0.75, 0.85), indicating strong agreement. However, kappa values varied substantially across facilities (range: 0.59, 0.92). Lower agreement was observed in facilities in Sokoto State and in areas with lower malaria prevalence and test positivity. Faint test lines, found in 8.8% of RDTs, were associated with a significantly increased likelihood of results misrecorded as negative. HCWs were more likely to misrecord RDT results as positive when a malaria diagnosis or antimalarial prescription had been made. Conclusion While overall agreement between facility registers and panel-interpreted RDT results was strong, the proportion of results misrecorded as positive and negative highlight the need for improved training, supportive supervision, and mechanisms to promote accurate RDT interpretation and recording. Targeted interventions are essential to ensure the reliability of routine malaria data and support national control efforts.
Investigating the Abbott-Bioline™ malaria antigen Pf/Pv rapid diagnostic test
Background Rapid Diagnostic Tests (RDT) have become an essential tool for the control of malaria worldwide. Their simplicity of use and their reliability make them ideal for the diagnosis of malaria in endemic areas. Numerous brands are now available on the market. In South East Asia, where both Plasmodium falciparum and Plasmodium vivax are prevalent, the Abbott-Bioline™ Malaria Ag Pf/Pv rapid diagnostic test (for the detection of Pf HRP2 and Pv LDH) is deployed widely but, after years of satisfactory performance, its recent sensitivity has been questioned after multiple false negative results were reported. Methods and results The study was conducted between October 2024 and January 2025. A field comparison with the First Response ® Malaria Ag pLDH/HRP2 RDT (for the detection of Pf HRP2 and Plasmodium Pan LDH) and microscopy (i.e. the gold standard) was conducted on the Thailand-Myanmar border where, until recent conflict, falciparum malaria was close to elimination. Overall (combining all field specimen), the Bioline RDT had a sensitivity of 0.18 and a specificity of 0.99 for P. falciparum . The corresponding figures for the First Response RDT were 0.89 and 0.93 respectively. For P. vivax malaria, the Bioline RDT had a sensitivity of 0.44 and a specificity of 0.99, while the First Response RDT had a sensitivity of 0.59 and a specificity of 0.98. In laboratory studies, using samples from patients or standard antigen panels (NIBSC antigens including histidine-rich protein 2 (HRP2 and P. vivax lactate dehydrogenase (PvLDH)), Bioline RDT consistently showed fainter result lines compared to the other brands of RDTs, at parasite densities between 208 and 1993/µL, and some tests had no visible lines at all. The Bioline RDT detected only 45.0% (9 of 20) cases of acute falciparum malaria and 74.0% (37 of 50) cases of acute vivax malaria whereas the First-response RDT, identified 90.3% (18 of 20) of P. falciparum and 84.0% (42 of 50) P. vivax cases. Conclusion The Abbott-Bioline™ Malaria Ag Pf/Pv RDT that were obtained in 2024 failed to detect microscopically confirmed cases of malaria and is not fit for purpose. This test should no longer be used and should be replaced by one with adequate performance.
Performance and challenges of malaria rapid diagnostic tests in endemic regions of Africa
Rapid diagnostic tests (RDTs) have revolutionized malaria diagnosis, playing a crucial role in improving timely treatment and supporting surveillance efforts, especially in resource-limited settings. However, the performance of RDTs can vary widely due to factors such as parasite genetic diversity, environmental conditions, and operational challenges. Understanding these variations is essential to ensuring accurate and reliable malaria diagnosis. This systematic review and meta-analysis critically evaluate the diagnostic performance of malaria RDTs across sub-Saharan Africa, identifying key gaps and proposing strategies for developing novel tests. By pooling data from 48 studies, the analysis quantifies the sensitivity and specificity of various RDT brands in different settings. The results reveal considerable variability, influenced by factors such as antigen persistence, cross-reactivity with other infections, and genetic polymorphism in the HRP2 gene, which can lead to false positives and negatives. The findings underscore the need for region-specific diagnostic strategies and the development of advanced diagnostic tools capable of detecting low-level parasitemia and differentiating between Plasmodium species. Emerging technologies and multi-platform approaches are recommended to enhance the accuracy and reliability of malaria diagnosis, ultimately contributing to more effective malaria control and elimination efforts in sub-Saharan Africa.
Prevalence of asymptomatic parasitaemia among household members of children under seasonal malaria chemoprevention coverage and comparison of the performance of standard rapid diagnostic tests versus ultrasensitive RDT for the detection of asymptomatic parasitaemia in Nanoro, Burkina Faso
Asymptomatic carriers of Plasmodium falciparum represent important parasite reservoirs maintaining malaria transmission in the community. This study aimed on the one hand to screen the other household members living with children under seasonal malaria chemoprevention (SMC) coverage in order to determine the level of malaria infection in this population and on the other hand to determine the appropriate type of rapid diagnostic test (RDT) for this screening to detect these asymptomatic carriers in the community. During the 2022 SMC campaign (July to October), a cross-sectional survey was carried out in 745 participants who were screened by ultrasensitive rapid diagnostic test (usRDT), standard rapid diagnostic test (rRDT) and microscopy. Out of them, 395 had microscopy results available and were included in the data analysis. The prevalence of asymptomatic carriers of asexual forms of Plasmodium falciparum was 26.58% (105/395) while sexual forms were found in 5.32% (21/395) of the study population. Children from 5 to 15 years had the highest prevalence of P. falciparum asexual forms 35.76% (59/165) compared with older participants. Malaria positivity rate for rRDT and usRDT was 29.40% (219/745) and 40.49% (305/745) respectively. The usRDT had a higher sensitivity than the rRDT (72.38% (95% CI 62.8–80.66) vs. 60.95% (95% CI 50.94–70.33)). In terms of specificity, rRDT had a higher specificity 82.41% (95% CI 77.53–86.62) versus 69.66% (95% CI 64.01–74.89) for usRDT. This study reports a high prevalence of parasite carriers in household members of children under SMC coverage in Nanoro, Burkina Faso. In conclusion, usRDT seems more appropriate for strategies based on detection and treatment of parasite carriers within the community.
Malaria in pregnancy (MiP) studies assessing the clinical performance of highly sensitive rapid diagnostic tests (HS-RDT) for Plasmodium falciparum detection
Background Rapid diagnostic tests (RDTs) are effective tools to diagnose and inform the treatment of malaria in adults and children. The recent development of a highly sensitive rapid diagnostic test (HS-RDT) for Plasmodium falciparum has prompted questions over whether it could improve the diagnosis of malaria in pregnancy and pregnancy outcomes in malaria endemic areas. Methods This landscape review collates studies addressing the clinical performance of the HS-RDT. Thirteen studies were identified comparing the HS-RDT and conventional RDT (co-RDT) to molecular methods to detect malaria in pregnancy. Using data from five completed studies, the association of epidemiological and pregnancy-related factors on the sensitivity of HS-RDT, and comparisons with co-RDT were investigated. The studies were conducted in 4 countries over a range of transmission intensities in largely asymptomatic women. Results Sensitivity of both RDTs varied widely (HS-RDT range 19.6 to 85.7%, co-RDT range 22.8 to 82.8% compared to molecular testing) yet HS-RDT detected individuals with similar parasite densities across all the studies including different geographies and transmission areas [geometric mean parasitaemia around 100 parasites per µL (p/µL)]. HS-RDTs were capable of detecting low-density parasitaemias and in one study detected around 30% of infections with parasite densities of 0–2 p/µL compared to the co-RDT in the same study which detected around 15%. Conclusion The HS-RDT has a slightly higher analytical sensitivity to detect malaria infections in pregnancy than co-RDT but this mostly translates to only fractional and not statistically significant improvement in clinical performance by gravidity, trimester, geography or transmission intensity. The analysis presented here highlights the need for larger and more studies to evaluate incremental improvements in RDTs. The HS-RDT could be used in any situation where co-RDT are currently used for P. falciparum diagnosis, if storage conditions can be adhered to.