scholarly journals The Role of Antigen Rapid Diagnostic Test in COVID-19 Diagnosis

2021 ◽  
Vol 1 (1) ◽  
pp. 108-111
Author(s):  
Ronni Mol Joji ◽  
Mohammad Shahid

Since the emergence of a novel infection due to the SARS-CoV-2 virus (COVID-19), the World Health Organization has urged countries to develop diagnostic tests to combat the pandemic. Molecular assays were developed following the release of the gene sequence of the virus in January 2020. Reverse transcription-quantitative PCR (RT-qPCR) is taken as the gold standard for the diagnosis of COVID-19. However, due to its limitations, highly sensitive methods for detecting antigens (antigen rapid diagnostic tests) have been developed that would help in a timely and accurate diagnosis. Antigen rapid diagnostic tests (Ag-RDTs) can help guide patient management at the point of care by random screening, re-testing, and timely decision-making in the field of public health. When the affordability and validity of the diagnostic assay are involved, no assay can show 100% correct results. Further studies need to be done to better understand the response of the Ag-RDTs in different settings. Nevertheless, Ag-RDTs can play a complementary role in the response and case management of COVID-19.

2002 ◽  
Vol 15 (1) ◽  
pp. 66-78 ◽  
Author(s):  
Anthony Moody

SUMMARY Malaria presents a diagnostic challenge to laboratories in most countries. Endemic malaria, population movements, and travelers all contribute to presenting the laboratory with diagnostic problems for which it may have little expertise available. Drug resistance and genetic variation has altered many accepted morphological appearances of malaria species, and new technology has given an opportunity to review available procedures. Concurrently the World Health Organization has opened a dialogue with scientists, clinicians, and manufacturers on the realistic possibilities for developing accurate, sensitive, and cost-effective rapid diagnostic tests for malaria, capable of detecting 100 parasites/μl from all species and with a semiquantitative measurement for monitoring successful drug treatment. New technology has to be compared with an accepted Rgold standardS that makes comparisons of sensitivity and specificity between different methods. The majority of malaria is found in countries where cost-effectiveness is an important factor and ease of performance and training is a major consideration. Most new technology for malaria diagnosis incorporates immunochromatographic capture procedures, with conjugated monoclonal antibodies providing the indicator of infection. Preferred targeted antigens are those which are abundant in all asexual and sexual stages of the parasite and are currently centered on detection of HRP-2 from Plasmodium falciparum and parasite-specific lactate dehydrogenase or Plasmodium aldolase from the parasite glycolytic pathway found in all species. Clinical studies allow effective comparisons between different formats, and the reality of nonmicroscopic diagnoses of malaria is considered.


Diagnostics ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 768
Author(s):  
Michael J. Kavanaugh ◽  
Steven E. Azzam ◽  
David M. Rockabrand

Malaria rapid diagnostic tests (RDTs) have had an enormous global impact which contributed to the World Health Organization paradigm shift from empiric treatment to obtaining a parasitological diagnosis prior to treatment. Microscopy, the classic standard, requires significant expertise, equipment, electricity, and reagents. Alternatively, RDT’s lower complexity allows utilization in austere environments while achieving similar sensitivities and specificities. Worldwide, there are over 200 different RDT brands that utilize three antigens: Plasmodium histidine-rich protein 2 (PfHRP-2), Plasmodium lactate dehydrogenase (pLDH), and Plasmodium aldolase (pALDO). pfHRP-2 is produced exclusively by Plasmodium falciparum and is very Pf sensitive, but an alternative antigen or antigen combination is required for regions like Asia with significant Plasmodium vivax prevalence. RDT sensitivity also decreases with low parasitemia (<100 parasites/uL), genetic variability, and prozone effect. Thus, proper RDT selection and understanding of test limitations are essential. The Center for Disease Control recommends confirming RDT results by microscopy, but this is challenging, due to the utilization of clinical laboratory standards, like the College of American Pathologists (CAP) and the Clinical Lab Improvement Act (CLIA), and limited recourses. Our focus is to provide quality assurance and quality control strategies for resource-constrained environments and provide education on RDT limitations.


2021 ◽  
Vol 12 ◽  
Author(s):  
Julio Flores ◽  
Juan Carlos Cancino ◽  
Leslie Chavez-Galan

Tuberculosis (TB) is still a severe public health problem; the current diagnostic tests have limitations that delay treatment onset. Lipoarabinomannan (LAM) is a glycolipid that is a component of the cell wall of the bacillus Mycobacterium tuberculosis, the etiologic agent of TB. This glycolipid is excreted as a soluble form in urine. The World Health Organization has established that the design of new TB diagnostic methods is one of the priorities within the EndTB Strategy. LAM has been suggested as a biomarker to develop diagnostic tests based on its identification in urine, and it is one of the most prominent candidates to develop point-of-care diagnostic test because urine samples can be easily collected. Moreover, LAM can regulate the immune response in the host and can be found in the serum of TB patients, where it probably affects a wide variety of host cell populations, consequently influencing the quality of both innate and adaptive immune responses during TB infection. Here, we revised the evidence that supports that LAM could be used as a tool for the development of new point-of-care tests for TB diagnosis, and we discussed the mechanisms that could contribute to the low sensitivity of diagnostic testing.


2020 ◽  
Vol 3 ◽  
pp. 8 ◽  
Author(s):  
Gerald Mboowa

On March 11, 2020 the World Health Organization (WHO) upgraded the status of the coronavirus disease 2019 (COVID-19) outbreak from epidemic to a global pandemic. This infection is caused by a novel coronavirus, SARS-CoV-2. Several rapid diagnostic tests have been developed at an astonishing pace; however, COVID-19 requires more highly specific rapid point-of-care diagnostic tests. This review describes the currently available testing approaches, as well as the available test assays including the Xpert® Xpress SARS-CoV-2 test (takes ~45 min) and Abbott ID COVID-19 test (5 min) as easy to use point-of-care tests for diagnosis of novel COVID-19 that have so far received the US Food and Drug Administration emergency use authorizations clearance. This review is correct as of the date published and will be updated as more diagnostic tests come to light.


2019 ◽  
Vol 26 (8) ◽  
Author(s):  
Matthew Bonaparte ◽  
Lingyi Zheng ◽  
Sanjay Garg ◽  
Bruno Guy ◽  
Yaniv Lustig ◽  
...  

Abstract Background In September 2018, the World Health Organization recommended that prevaccination screening be used with the tetravalent dengue vaccine (CYD-TDV), to ensure that only individuals with evidence of prior dengue infection (PDI) are vaccinated. Dengue rapid diagnostic tests (RDTs) would offer a potential solution for prevaccination screening at the point-of-care, but data on performance of available RDTs for identifying PDI are limited. We determined the suitability of four dengue RDTs and two conventional enzyme-linked immunosorbent assays (ELISAs) to identify PDI and evaluated cross-reactivity with co-circulating flaviviruses. Methods: Specificity was assessed using 534 dengue-negative [determined by 50% plaque reduction neutralization test (PRNT50)] serum samples from USA (n = 229) and dengue-endemic regions (n = 305). Sensitivity was assessed using 270 samples from recent (n = 90) or remote (n = 90) virologically confirmed prior dengue cases, and dengue PRNT50-positive samples (n = 90). Cross-reactivity was assessed in dengue-seronegative samples that were seropositive for yellow fever (n = 57), Japanese encephalitis (n = 37), West Nile (n = 59) or Zika (n = 41). Results: Dengue IgG RDTs and the Panbio ELISA exhibited favourable specificities (99–100%), higher than the Focus ELISA (95%). The RDTs had variable sensitivities (40–70%) that were lower than those of the ELISAs (≥90%). Cross-reactivity to other flaviviruses was low with RDTs (≤7%), but more significant with ELISAs (up to 51% for West Nile and 34% for Zika). No cross-reactivity to any of the four closely related flaviviruses was observed with the CTK Biotech RDT. For each SeroTest, sensitivity appeared similar in samples from individuals with recent (&lt;13 months) vs remote (3–4 years) virologically confirmed PDI. Conclusions: In general, dengue IgG RDTs were found to be more specific and less cross-reactive than the ELISAs, but the latter were more sensitive for identifying PDI cases. Currently available RDTs could be temporizing tools for rapid and safe prevaccination screening until improved RDTs with increased sensitivity become available.


2021 ◽  
Vol 12 ◽  
Author(s):  
Fernando Echegaray ◽  
Peter Laing ◽  
Samantha Hernandez ◽  
Sully Marquez ◽  
Amanda Harris ◽  
...  

The only licensed dengue vaccine, Dengvaxia®, increases risk of severe dengue when given to individuals without prior dengue virus (DENV) infection but is protective against future disease in those with prior DENV immunity. The World Health Organization has recommended using rapid diagnostic tests (RDT) to determine history of prior DENV infection and suitability for vaccination. Dengue experts recommend that these assays be highly specific (≥98%) to avoid erroneously vaccinating individuals without prior DENV infection, as well as be sensitive enough (≥95%) to detect individuals with a single prior DENV infection. We evaluated one existing and two newly developed anti-flavivirus RDTs using samples collected &gt;6 months post-infection from individuals in non-endemic and DENV and ZIKV endemic areas. We first evaluated the IgG component of the SD BIOLINE Dengue IgG/IgM RDT, which was developed to assist in confirming acute/recent DENV infections (n=93 samples). When evaluated following the manufacturer’s instructions, the SD BIOLINE Dengue RDT had 100% specificity for both non-endemic and endemic samples but low sensitivity for detecting DENV seropositivity (0% non-endemic, 41% endemic). Sensitivity increased (53% non-endemic, 98% endemic) when tests were allowed to run beyond manufacturer recommendations (0.5 up to 3 hours), but specificity decreased in endemic samples (36%). When tests were evaluated using a quantitative reader, optimal specificity could be achieved (≥98%) while still retaining sensitivity at earlier timepoints in non-endemic (44-88%) and endemic samples (31-55%). We next evaluated novel dengue and Zika RDTs developed by Excivion to detect prior DENV or ZIKV infections and reduce cross-flavivirus reactivity (n=207 samples). When evaluated visually, the Excivion Dengue RDT had sensitivity and specificity values of 79%, but when evaluated with a quantitative reader, optimal specificity could be achieved (≥98%) while still maintaining moderate sensitivity (48-75%). The Excivion Zika RDT had high specificity (&gt;98%) and sensitivity (&gt;93%) when evaluated quantitatively, suggesting it may be used alongside dengue RDTs to minimize misclassification due to cross-reactivity. Our findings demonstrate the potential of RDTs to be used for dengue pre-vaccination screening to reduce vaccine-induced priming for severe dengue and show how assay design adaptations as well quantitative evaluation can further improve RDTs for this purpose.


2018 ◽  
Vol 57 (1) ◽  
Author(s):  
Radha Rajasingham ◽  
Rachel M. Wake ◽  
Tafese Beyene ◽  
Andrew Katende ◽  
Emilio Letang ◽  
...  

ABSTRACT Over the past ten years, standard diagnostics for cryptococcal meningitis in HIV-infected persons have evolved from culture to India ink to detection of cryptococcal antigen (CrAg), with the recent development and distribution of a point-of-care lateral flow assay. This assay is highly sensitive and specific in cerebrospinal fluid (CSF), but is also sensitive in the blood to detect CrAg prior to meningitis symptoms. CrAg screening of HIV-infected persons in the blood prior to development of fulminant meningitis and preemptive treatment for CrAg-positive persons are recommended by the World Health Organization and many national HIV guidelines. Thus, CrAg testing is occurring more widely, especially in resource-limited laboratory settings. CrAg titer predicts meningitis and death and could be used in the future to customize therapy according to burden of infection.


Author(s):  
Lara Bittmann

On December 31, 2019, WHO was informed of cases of pneumonia of unknown cause in Wuhan City, China. A novel coronavirus was identified as the cause by Chinese authorities on January 7, 2020 and was provisionally named "2019-nCoV". This new Coronavirus causes a clinical picture which has received now the name COVID-19. The virus has spread subsequently worldwide and was explained on the 11th of March, 2020 by the World Health Organization to the pandemic.


2021 ◽  
Vol 29 (Supplement_1) ◽  
pp. i45-i46
Author(s):  
A Peletidi ◽  
R Kayyali

Abstract Introduction Obesity is one of the main cardiovascular disease (CVD) risk factors.(1) In primary care, pharmacists are in a unique position to offer weight management (WM) interventions. Greece is the European country with the highest number of pharmacies (84.06 pharmacies per 100,000 citizens).(2) The UK was chosen as a reference country, because of the structured public health services offered, the local knowledge and because it was considered to be the closest country to Greece geographically, unlike Australia and Canada, where there is also evidence confirming the potential role of pharmacists in WM. Aim To design and evaluate a 10-week WM programme offered by trained pharmacists in Patras. Methods This WM programme was a step ahead of other interventions worldwide as apart from the usual measuring parameters (weight, body mass index, waist circumference, blood pressure (BP)) it also offered an AUDIT-C and Mediterranean diet score tests. Results In total,117 individuals participated. Of those, 97.4% (n=114), achieved the programme’s aim, losing at least 5% of their initial weight. The mean % of total weight loss (10th week) was 8.97% (SD2.65), and the t-test showed statistically significant results (P&lt;0.001; 95% CI [8.48, 9.45]). The programme also helped participants to reduce their waist-to-height ratio, an early indicator of the CVD risk in both male (P=0.004) and female (P&lt;0.001) participants. Additionally, it improved participants’ BP, AUDIT-C score and physical activity levels significantly (P&lt;0.001). Conclusion The research is the first systematic effort in Greece to initiate and explore the potential role of pharmacists in public health. The successful results of this WM programme constitute a first step towards the structured incorporation of pharmacists in public’s health promotion. It proposed a model for effectively delivering public health services in Greece. This study adds to the evidence in relation to pharmacists’ CVD role in public health with outcomes that superseded other pharmacy-led WM programmes. It also provides the first evidence that Greek pharmacists have the potential to play an important role within primary healthcare and that after training they are able to provide public health services for both the public’s benefit and their clinical role enhancement. This primary evidence should support the Panhellenic Pharmaceutical Association, to “fight” for their rights for an active role in primary care. In terms of limitations, it must be noted that the participants’ collected data were recorded by pharmacists, and the analysis therefore depended on the accuracy of the recorded data, in particular on the measurements or calculations obtained. Although the sample size was achieved, it can be argued that it is small for the generalisation of findings across Greece. Therefore, the WM programme should be offered in other Greek cities to identify if similar results can be replicated, so as to consolidate the contribution of pharmacists in promoting public health. Additionally, the study was limited as it did not include a control group. Despite the limitations, our findings provide a model for a pharmacy-led public health programme revolving around WM that can be used as a model for services in the future. References 1. Mendis S, Puska P, Norrving B, World Health Organization., World Heart Federation., World Stroke Organization. Global atlas on cardiovascular disease prevention and control [Internet]. Geneva: World Health Organization in collaboration with the World Heart Federation and the World Stroke Organization; 2011 [cited 2018 Jun 26]. 155 p. Available from: http://www.who.int/cardiovascular_diseases/publications/atlas_cvd/en/ 2. Pharmaceutical Group of the European Union. Pharmacy with you throughout life:PGEU Annual Report [Internet]. 2015. Available from: https://www.pgeu.eu/en/library/530:annual-report-2015.html


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Pojchanun Kanitthamniyom ◽  
Pei Yun Hon ◽  
Aiwu Zhou ◽  
Mohammad Yazid Abdad ◽  
Zhi Yun Leow ◽  
...  

AbstractCarbapenemase-producing Enterobacteriaceae (CPE) are a group of drug-resistant Gram-negative pathogens that are classified as a critical threat by the World Health Organization (WHO). Conventional methods of detecting antibiotic-resistant pathogens do not assess the resistance mechanism and are often time-consuming and laborious. We have developed a magnetic digital microfluidic (MDM) platform, known as MDM Carba, for the identification of CPE by measuring their ability to hydrolyze carbapenem antibiotics. MDM Carba offers the ability to rapidly test CPE and reduce the amount of reagents used compared with conventional phenotypic testing. On the MDM Carba platform, tests are performed in droplets that function as reaction chambers, and fluidic operations are accomplished by manipulating these droplets with magnetic force. The simple droplet-based magnetic fluidic operation allows easy system automation and simplified hands-on operation. Because of the unique “power-free” operation of MDM technology, the MDM Carba platform can also be operated manually, showing great potential for point-of-care testing in resource-limited settings. We tested 27 bacterial isolates on the MDM Carba platform, and the results showed sensitivity and specificity that were comparable to those of the widely used Carba NP test. MDM Carba may shorten the overall turnaround time for CPE identification, thereby enabling more timely clinical decisions for better clinical outcomes. MDM Carba is a technological platform that can be further developed to improve diagnostics for other types of antibiotic resistance with minor modifications.


Sign in / Sign up

Export Citation Format

Share Document