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Accelerating diagnostics in a time of crisis : the response to COVID-19 and a roadmap for future pandemics
\"By presenting chapter-specific roadmaps, this book offers a behind-the-scenes chronology of the response to COVID-19 and provides a rubric for future pandemic response. Targeted at lay and scientific audiences, reflections and lessons learned grant the reader an opportunity to leverage this knowledge and improve the outcomes of future pandemics\"-- Provided by publisher.
BOOK
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.
Journal Article
Development and Optimization of a Cost-Effective Electrochemical Immunosensor for Rapid COVID-19 Diagnosis
The coronavirus disease (COVID-19) pandemic has created an urgent need for rapid, accurate, and cost-effective diagnostic tools. In this study, an economical electrochemical immunosensor for the rapid diagnosis of COVID-19 was developed and optimized based on charge transfer resistance (Rct) values obtained by electrochemical impedance spectroscopy (EIS) from the interaction between antibodies (anti-SARS-CoV-2) immobilized as a bioreceptor and the virus (SARS-CoV-2). The sensor uses modified pencil graphite electrodes (PGE) coated with poly(4-hydroxybenzoic acid), anti-SARS-CoV-2, and silver nanoparticles. The immobilization of anti-SARS-CoV-2 antibodies was optimized at a concentration of 1:250 for 30 min, followed by blocking the surface with 0.01% bovine serum albumin for 10 min. The optimal conditions for virus detection in clinical samples were a 1:10 dilution with a response time of 20 min. The immunosensor responded linearly in the range of 0.2–2.5 × 106 particles/μL. From the relationship between the obtained signal and the concentration of the analyzed sample, the limit of detection (LOD) and limit of quantification (LOQ) obtained were 1.21 × 106 and 4.04 × 106 particles/μL, respectively. The device did not cross-react with other viruses, including Influenza A and B, HIV, and Vaccinia virus. The relative standard deviation (RSD) of the six immunosensors prepared using the shared-pool sample was 3.87. Decreases of 22.3% and 12.4% were observed in the response values of the ten immunosensors stored at 25 °C and 4.0 °C, respectively. The sensor provides timely and accurate results with high sensitivity and specificity, offering a cost-effective alternative to the existing diagnostic methods.
Journal Article
Diagnostic accuracy of the OnSite Dengue Ag rapid test in symptomatic patients from Dhaka, Bangladesh
Background
Dengue fever poses an extreme public health risk in the tropical and subtropical zones around the world. Prompt and correct diagnosis is critical for dengue case management and control. Dengue NS1 antigen detection is the basic diagnostic method for dengue. Although PCR is the gold standard for detecting dengue, it is expensive, equipment-intensive, and requires skilled personnel posing major challenges for many healthcare facilities. A rapid and affordable diagnostic method for dengue is essential to address these limitations.
Methods
This study examine the clinical performance of OnSite
®
Dengue Ag Rapid Test (developed by CTK Biotech Inc., Poway, CA, USA) utilizing 316 symptomatic patients from three outreach centers of icddr, b diagnostic unit of Dhaka, Bangladesh. RT-PCR was used as the gold standard and Bioline™ Dengue NS1 Ag (developed by Abbott Laboratories, Illinois, U.S.) was used as comparator.
Results
The Overall sensitivity and specificity of OnSite
®
Dengue Ag Rapid Test were 96.93% (95% CI: 95.03%- 98.83%) and 99.35% (95% CI: 98.46-100.23%) respectively against RT-PCR. These values were slightly higher than those of comparator device, which demonstrated sensitivity and specificity of 93.87% (95% CI: 91.22%-96.51%) and 96.73% (95% CI: 94.77%-98.69%) respectively. Between two and five days following the onset of fever, the RDT kit can detect patients and is able to detect dengue NS1 even in samples with very low viral load (high RT-PCR Ct values ≤ 36.96), indicating its high sensitivity and accuracy.
Conclusions
OnSite
®
Dengue Ag Rapid Test demonstrated substantial potential for clinical diagnosis of symptomatic dengue patients, providing a fast, cheap and reliable detection method. Its simplicity, ease of use and minimal equipment requirements make it highly suitable for use in diverse healthcare settings, particularly in resource-limited areas around the world.
Journal Article
Antigen rapid diagnostic test monitoring for SARS‐CoV‐2 in asymptomatic and fully vaccinated cancer patients: Is it cost‐effective?
Background Routine testing for cancer patients not presenting COVID‐19‐related symptoms and fully vaccinated for SARS‐CoV‐2 prior to cancer treatment is controversial. Methods In this retrospective study we evaluated whether antigen‐rapid‐diagnostic‐test (Ag‐RDT) monitoring for SARS‐CoV‐2 in a large cohort of consecutive asymptomatic (absence of SARS‐CoV‐2‐related symptoms such as fever, cough, sore throat or nasal congestion) and fully vaccinated cancer patients enrolled in a short period during cancer treatment has an impact on the therapeutic path of cancer patients. Results From December 27, 2021, to February 11, 2022, 2439 cancer patients were screened through Ag‐RDT for SARS‐CoV‐2 before entering the hospital for systemic treatment. Fifty‐three patients (2.17%) tested positive, of whom 7 (13.2%) subsequently developed COVID‐related symptoms, generally mild. Cancer treatment was discontinued, as a precaution, in 49 patients (92.5%) due to the test positivity. Conclusion SARS‐CoV‐2 screening in asymptomatic and fully vaccinated cancer patients during systemic treatment appeared to be not cost‐effective: the low rate of SARS‐CoV‐2 positive patients and the low percentage of overt associated infection do not seem proportional to the direct costs (nursing work for swabs, costs of materials and patient monitoring) and indirect costs (dedicated rooms, extension of waiting times for patients and oncologists in delivering therapy as well as its discontinuation in the positive ones). It can, on the other hand, be detrimental when systemic cancer treatment is suspended as a precaution. Given the small number of patients testing positive and the rapid and favorable trend of the infection, it is recommended to always consider continuing systemic oncological treatment, especially when this impacts patient survival as in the adjuvant or neoadjuvant setting. SARS‐CoV‐2 screening in asymptomatic and fully‐vaccinated cancer patients during systemic treatment appeared to be not cost‐effective.
Journal Article
Novel Rapid Test for Detecting Carbapenemase
We developed a carbapenemase test based on the ability of imipenem to inhibit noncarbapenemase β-lactamases. The test uses bacterial isolates with a fluorescent β-lactamase substrate, producing objective results with 100% sensitivity and specificity in 10 minutes. The assay is inexpensive and consists of only 1 mixing step.
Journal Article
Development of a Dengue Virus Serotype-Specific Non-Structural Protein 1 Capture Immunochromatography Method
Four serotypes of dengue virus (DENV), type 1 to 4 (DENV-1 to DENV-4), exhibit approximately 25–40% of the difference in the encoded amino acid residues of viral proteins. Reverse transcription of RNA extracted from specimens followed by PCR amplification is the current standard method of DENV serotype determination. However, since this method is time-consuming, rapid detection systems are desirable. We established several mouse monoclonal antibodies directed against DENV non-structural protein 1 and integrated them into rapid DENV detection systems. We successfully developed serotype-specific immunochromatography systems for all four DENV serotypes. Each system can detect 104 copies/mL in 15 min using laboratory and clinical isolates of DENV. No cross-reaction between DENV serotypes was observed in these DENV isolates. We also confirmed that there was no cross-reaction with chikungunya, Japanese encephalitis, Sindbis, and Zika viruses. Evaluation of these systems using serum from DENV-infected individuals indicated a serotype specificity of almost 100%. These assay systems could accelerate both DENV infection diagnosis and epidemiologic studies in DENV-endemic areas.
Journal Article
Laboratory Evaluation and Field Testing of Dengue NS1 and IgM/IgG Rapid Diagnostic Tests in an Epidemic Context in Senegal
In Senegal, the burden of dengue is increasing and expanding. As case management and traditional diagnostic techniques can be difficult to implement, rapid diagnostic tests (RDTs) deployed at point of care are ideal for investigating active outbreaks. The aim of this study was to evaluate the diagnostic performance of the Dengue NS1 and Dengue IgM/IgG RDTs on the serum/plasma samples in a laboratory setting and in the field. During laboratory evaluation, performance of the NS1 RDT was assessed using NS1 ELISA as the gold standard. Sensitivity and specificity were 88% [75–95%] and 100% [97–100%], respectively. Performance of the IgM/IG RDT was assessed using the IgM Antibody Capture (MAC) ELISA, indirect IgG, and PRNT as gold standards. The IgM and IgG test lines respectively displayed sensitivities of 94% [83–99%] and 70% [59–79%] and specificities of 91% [84–95%] and 91% [79–98%]. In the field, the Dengue NS1 RDT sensitivity and specificity was 82% [60–95%] and 75% [53–90%], respectively. The IgM and IgG test lines displayed sensitivities of 86% [42–100%] and 78% [64–88%], specificities of 85% [76–92%] and 55% [36–73%], respectively. These results demonstrate that RDTs are ideal for use in a context of high prevalence or outbreak setting and can be implemented in the absence of a confirmatory test for acute and convalescent patients.
Journal Article
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.
Journal Article
The performance of a new rapid interferon gamma release assay based on fluorescence immunochromatography for Mycobacterium tuberculosis infection testing in village doctors in China
The AIMTB rapid test assay is an emerging test, which adopted a fluorescence immunochromatographic assay to measure interferon-γ (IFN-γ) production following stimulation of effector memory T cells in whole blood by mycobacterial proteins. The aim of this article was to explore the ability of AIMTB rapid test assay in detecting Mycobacterium tuberculosis (MTB) infection compared with the widely applied QuantiFERON-TB Gold Plus (QFT-Plus) test among rural doctors in China. In total, 511 participants were included in the survey. The concordance between the QFT-Plus test and the AIMTB rapid test assay was 94.47% with a Cohen’s kappa coefficient (κ) of 0.84 (95% CI, 0.79–0.90). Improved concordance between the two tests was observed in males and in participants with 26 or more years of service as rural doctors. The quantitative values of the QFT-Plus test was higher in individuals with a result of QFT-Plus-/AIMTB+ as compared to those with a result of QFT-Plus-/AIMTB- (p < 0.001). Overall, our study found that there was an excellent consistency between the AIMTB rapid test assay and the QFT-Plus test in a Chinese population. As the AIMTB rapid test assay is fast and easy to operate, it has the potential to improve latent tuberculosis infection testing and treatment at the community level in resource-limited settings.
Journal Article