scholarly journals Evaluation of the validity of Ag PANBIO-COVID19 in the diagnosis of SARS-CoV-2 infection in asymptomatic or mildly infected patients

Author(s):  
Paula Gras-Valenti ◽  
Inmaculada Vidal ◽  
Inés Montiel-Higuero ◽  
Isabel Escribano ◽  
Natividad Algado-Selles ◽  
...  

Objective. To assess the validity of SARS-CoV-2 Antigen (Ag) detection for the diagnosis of SARS-CoV-2 infection in mildly infected or asymptomatic patients. Material and methods. Observational study to evaluate diagnostic tests. Non-hospitalized patients with indication for diagnostic testing for SARS-CoV-2 infection were included. The diagnostic test to be evaluated was the determination of Ag and as a reference standard to determine the presence of viral RNA the RT-PCR was used. Results. A total of 494 patients were included. Of these 71.5% (353/494) had symptoms and 28.5% (141/494) were asymptomatic (presurgery screening (35/494) and confirmed case-contact (106/494). The overall sensitivity of the Ag test was 61.1% and the specificity was 99.7%. The sensitivity and specificity in the asymptomatic group were 40% and 100% respectively, and in the symptomatic group 63.5% and 99.6% respectively. In turn, the sensitivity and specificity in the group of symptomatic patients varied according to the time of symptom evolution: in patients with recent symptoms, they were 71.4% and 99.6% respectively, while in patients with symptoms of more than 5 days of evolution, they were 26.7% and 100% respectively. In all groups studied, the presence of antigen is associated with a high viral load (Ct<30 cycles). Conclusions. The use of Ag detection test is not indicated for the diagnosis of SARS-CoV-2 infection in asymptomatic patients or with symptoms of more than 5 days of evolution, but it could be useful in patients with symptoms of 1-5 days of evolution.

2015 ◽  
Vol 53 (12) ◽  
pp. 3738-3749 ◽  
Author(s):  
Caroline Chartrand ◽  
Nicolas Tremblay ◽  
Christian Renaud ◽  
Jesse Papenburg

Respiratory syncytial virus (RSV) rapid antigen detection tests (RADT) are extensively used in clinical laboratories. We performed a systematic review and meta-analysis to evaluate the accuracy of RADTs for diagnosis of RSV infection and to determine factors associated with accuracy estimates. We searched EMBASE and PubMed for diagnostic-accuracy studies of commercialized RSV RADTs. Studies reporting sensitivity and specificity data compared to a reference standard (reverse transcriptase PCR [RT-PCR], immunofluorescence, or viral culture) were considered. Two reviewers independently extracted data on study characteristics, diagnostic-accuracy estimates, and study quality. Accuracy estimates were pooled using bivariate random-effects regression models. Heterogeneity was investigated with prespecified subgroup analyses. Seventy-one articles met inclusion criteria. Overall, RSV RADT pooled sensitivity and specificity were 80% (95% confidence interval [CI], 76% to 83%) and 97% (95% CI, 96% to 98%), respectively. Positive- and negative-likelihood ratios were 25.5 (95% CI, 18.3 to 35.5) and 0.21 (95% CI, 0.18 to 0.24), respectively. Sensitivity was higher in children (81% [95% CI, 78%, 84%]) than in adults (29% [95% CI, 11% to 48%]). Because of this disparity, further subgroup analyses were restricted to pediatric data (63 studies). Test sensitivity was poorest using RT-PCR as a reference standard and highest using immunofluorescence (74% versus 88%;P< 0.001). Industry-sponsored studies reported significantly higher sensitivity (87% versus 78%;P= 0.01). Our results suggest that the poor sensitivity of RSV RADTs in adults may preclude their use in this population. Furthermore, industry-sponsored studies and those that did not use RT-PCR as a reference standard likely overestimated test sensitivity.


Author(s):  
Ajitha Pottirayil ◽  
Shankar A. S. ◽  
Shaji Kannoth ◽  
Poorna Prasad ◽  
Sharath Kumar B. Jaikar ◽  
...  

Background: COVID-19 patients experience cytokine storm which cause pulmonary and extra-pulmonary complications even with currently available of standard of care. Additional antiviral and immune boosters are the need of hour to treat COVID-19 and to prevent post covid complications.Methods: In this study we enrolled 40 asymptomatic to mild COVID-19 patients to receive azadvir herbal steam inhaler along with standard of care. We evaluated the benefits of azadvir herbal steam inhaler by assessing RT-PCR conversion, clinical outcomes and improvement in immune markers (LDH, CRP, D-DIMER).Results: At the end of the study the immune markers improved significantly in study patients. In mild symptomatic cases IL-6 was 23.2 pg/ml on day 0 and 21.8 pg/ml on day 14. Reduction in IL-6 in mild symptomatic patients was statistically highly significant (p=0.0056). Mean IL-6 in asymptomatic patients was 22.3 pg/ml on day 0 and 21.1 pg/ml on day 14. Reduction in IL-6 in asymptomatic patients was statistically highly significant (p=0.0035).  Mean D-dimer was showing decreasing trend from day 0 to day 14 in mild symptomatic patients. In asymptomatic patients D dimer was 0.8 µg/ml on day 0 and 0.6 µg/ml on day 14. D-dimer decreased significantly from day 0 to day 14 (p value =0.0013). Mean LDH values on day 0 in mild symptomatic patients was 319.4 U/l and 219.3 on day 14. The reduction in LDH values in mild symptomatic patients is statistically significant (p value <0.0122). In asymptomatic patients mean LDH values on day 0 was 237 U/l and 194 U/l on day 14. The reduction in LDH values in asymptomatic group was statistically significant. Mean CRP values in mild symptomatic patients on day 0 was 12.2 mg/l and 3.8 mg/l on day 14. There was significant reduction in CRP values in mild symptomatic group which was statistically significant (p value =0.0546). Mean CRP values in asymptomatic patients on day 0 was 4.9 mg/l and 2.8 mg/l on day 14. There was significant reduction in mean CRP in asymptomatic patients which was statistically significant (p value =0.0446). In the present study all 40 patients (100%) cleared the virus and became negative for RT PCR test within 6 days. None of the patients progressed to severe COVID-19 and none of the patients succumbed to the disease.Conclusions: Azadvir accelerated recovery of COVID-19 patients by RT-PCR conversion, early improvement in clinical symptoms and immune markers in this study. This study results clearly indicates that azadvir has antiviral, immune booster activity and has definitive role in the management of asymptomatic to mild COVID-19 patients along with standard of care (CTRI no. CTRI/2020/06/026181).


2022 ◽  
Vol 13 (1) ◽  
pp. 13-18
Author(s):  
Jayasri Helen Gali ◽  
Manasa Musku ◽  
Devireddy Pallavi Reddy ◽  
Vimala Thomas ◽  
Ehsan Ahmed Khan

Background: Emergence of variants with specific mutations in key epitopes in the spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) raises concerns pertinent to its severity. Aims and Objectives: To assess the demographics, clinico-radiological pattern, and outcome of reverse transcription-polymerase chain reaction (RT-PCR) positive isolated coronavirus disease 2019 (COVID-19) patients arrived from the United Kingdom (UK). Materials and Methods: A cross-sectional, observational study was conducted in RT-PCR positive COVID-19 patients arrived from the UK, from December 2020 to February 2021. Nasopharyngeal samples of all patients were sent for whole-genome sequencing of SARS-CoV-2. The aimed parameters were compared between the B.1.17 positive and non-B.1.1.7 groups, among the people, arrived from the UK. All statistical tests with P<0.05 were considered significant. Results: A total of 59 SARS-CoV2 infected patients, who arrived from the UK, were isolated from December 2020 to February 2021 at Telangana Institute of Medical Sciences hospital, Hyderabad, were enrolled in the study. Of these, 27 patients (mean age-31.81±11.28 years) were infected with the B.1.1.7, diagnosed by whole genomic sequencing. Males were predominant in our study. Personal habits such as smoking, alcohol intake were higher among the sequenced group with a significant P<0.05. The most common symptoms observed in the sequenced group were cough (22.22%), sore throat (22.22%), cold (11.11%), fever (11.11%), and in the unsequenced group were cough (22.22%), cold (6.25%), fever (6.25%). In the sequenced group, chest X-ray posteroanterior view was normal in 74%, patchy ground-glass opacities was observed in 25.92% patients, whereas in the unsequenced group it was 84.37% and 15.62%, respectively. Asymptomatic patients, observed in the sequenced and unsequenced group were 48.18% and 78.12%, respectively, and symptomatic patients were 51.85% and 21.87%, respectively. We found a statistically significant difference between sequenced and unsequenced patients in the asymptomatic group with a significant P<0.05. In the sequenced and unsequenced group, mild cases were 48.18% and 18.75%, moderate cases were 3.7% and 3.12%, respectively. We found no evidence of an association between disease severity and lineage B.1.17. Conclusion: Our data, within the context and limitations of a real-world study, provide initial reassurance that severity in hospitalized patients with B.1.1.7 is not markedly different from severity in those without B.1.1.7.


2021 ◽  
Vol 9 ◽  
Author(s):  
Ada Melo-Vallès ◽  
Clara Ballesté-Delpierre ◽  
Jordi Vila

On March 12, the World Health Organization declared a pandemic following the exponential increase of SARS-CoV-2 cases. The rapid spread of the virus is due to both its high infectivity and the free circulation of unrecognized infectious cases. Thus, diagnostic testing is a key element to prevent further dissemination of the virus. Urged by WHO's call, laboratories worldwide have been working on nucleic acid tests protocols and immunoassays that became available, albeit poorly validated, within a comparatively short time. Since then, external studies evaluating these diagnostic tests have been published. The present study is a review of the COVID-19 diagnostic approaches, discussing both direct and indirect microbiological diagnoses. A compendium of the literature on commercial assays kits available to date is provided together with the conclusions drawn as well as RT-PCR protocols published by the WHO. Briefly, diagnostic accuracy varies according to time elapsed since symptom onset and evolves together with understanding of the COVID-19 disease. Taking into account all these variables will allow determining the most adequate diagnostic test to use and how to optimize diagnostic testing for COVID-19.


2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Jira Chansaenroj ◽  
Ritthideach Yorsaeng ◽  
Nawarat Posuwan ◽  
Jiratchaya Puenpa ◽  
Natthinee Sudhinaraset ◽  
...  

Abstract Background Efficient monitoring and control of coronavirus disease 2019 (COVID-19) require access to diagnostic tests, and serological diagnostic testing is desirable. In the current study, antibodies were investigated in patients recently diagnosed with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Methods Cross-sectional data were obtained from 245 patients in whom SARS-CoV-2 infection had been confirmed via real-time reverse transcriptase-polymerase chain reaction between March and October 2020. Serum samples were acquired between 2 and 60 days following the onset of COVID-19 symptoms or the first detection of SARS-CoV-2 in asymptomatic patients. All specimens were tested simultaneously using an IgM/IgG rapid diagnostic test (RDT), IgG nucleocapsid protein-based chemiluminescent microparticle immunoassay (CMIA), IgG, and IgA spike protein-based enzyme-linked immunosorbent assays (ELISAs). Blood donor samples obtained in 2018 were used as negative controls. Results The sensitivity and specificity of the RDT IgG were compared with the IgG immunoassays as standards. The RDT IgG exhibited 97.5% sensitivity and 89.4% specificity compared with a CMIA IgG, 98.4% sensitivity, and 78.8% specificity compared with an ELISA IgG. IgM, IgG, and IgA seropositivity rates were low between 1 and 2 weeks after COVID-19 symptom onset or the detection of SARS-CoV-2 RNA. IgM seropositivity rate began decreasing after 4 weeks, whereas IgG and IgA seropositivity rate remained at appreciable levels over the 8-week study period. No cross-reactivity with seasonal coronaviruses was detected. Conclusions IgG RDT alone or combined with molecular diagnostic tests may be useful for identifying recent SARS-CoV-2 infection.


2021 ◽  
Author(s):  
Sharonjit Kaur Dhillon ◽  
Petra Schelstraete ◽  
Laura Cornelissen ◽  
Yves Lafort ◽  
Jesper Bonde ◽  
...  

Background The comparative performance of saliva and nasopharyngeal samples for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection by reverse transcriptase polymerase chain reaction (RT-PCR) in children remains unclear. As schools reopen around the world, there is an interest in the use of saliva samples for detection of SARS-CoV-2 in children to circumvent barriers with nasopharyngeal sampling. We systematically reviewed the literature to understand the performance of saliva sampling using RT-PCR on naso- and/or oropharyngeal swabs as the reference standard. Methods Articles from PubMed/MEDLINE and Living Evidence were accessed until 28th April 2021. A search method without restriction to children population was applied and during the review phase, if a study included patients <18 years old, authors were contacted to provide additional information on the subset of children. Studies were eligible if they reported on matched saliva and naso- and/or oropharyngeal samples, taken from the same patient on the same day. Studies using other respiratory samples such as sputum samples were excluded. Each paired patient sample had to be tested on the same RT-PCR platform. Results Ten studies were included, comprising 1486 matched saliva and on naso- and/or oropharyngeal pairs from children aged 0 to 18 years old. The pooled absolute sensitivity and specificity of saliva sampling using RT-PCR on nasopharyngeal samples as the reference standard was 84.5% (95% CI; 78.0%-90.3%) and 99.5% (95% CI; 98.2%-100.0%). Comparable performance of saliva to nasopharyngeal samples was shown in both symptomatic and asymptomatic children. Stratified analyses of various covariates showed no significant differences. Discussion Our pooled accuracy estimates of RT-PCR SARS-CoV-2 testing on saliva in children did not seem to be different from meta-analyses of studies that enrolled mainly adults. Saliva could potentially be considered an alternative sampling method for screening in children and to pick up those with high viral load.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
J. Singh ◽  
A. K. Yadav ◽  
A. Pakhare ◽  
P. Kulkarni ◽  
L. Lokhande ◽  
...  

AbstractTo meet the unprecedented requirement of diagnostic testing for SARS-CoV-2, a large number of diagnostic kits were authorized by concerned authorities for diagnostic use within a short period of time during the initial phases of the ongoing pandemic. We undertook this study to evaluate the inter-test agreement and other key operational features of 5 such commercial kits that have been extensively used in India for routine diagnostic testing for COVID-19. The five commercial kits were evaluated, using a panel of positive and negative respiratory samples, considering the kit provided by National Institute of Virology, Indian Council of Medical Research (2019-nCoV Kit) as the reference. The positive panel comprised of individuals who fulfilled the 3 criteria of being clinically symptomatic, having history of contact with diagnosed cases and testing positive in the reference kit. The negative panel included both healthy and disease controls, the latter being drawn from individuals diagnosed with other respiratory viral infections. The same protocol of sample collection, same RNA extraction kit and same RT-PCR instrument were used for all the kits. Clinical samples were collected from a panel of 92 cases and 60 control patients, who fulfilled our inclusion criteria. The control group included equal number of healthy individuals and patients infected with other respiratory viruses (n = 30, in each group). We observed varying sensitivity and specificity among the evaluated kits, with LabGun COVID-19 RT-PCR kit showing the highest sensitivity and specificity (94% and 100% respectively), followed by TaqPath COVID-19 Combo and Allplex 2019-nCoV assays. The extent of inter-test agreement was not associated with viral loads of the samples. Poor correlation was observed between Ct values of the same genes amplified using different kits. Our findings reveal the presence of wide heterogeneity and sub-optimal inter-test agreement in the diagnostic performance of the evaluated kits and hint at the need of adopting stringent standards for fulfilling the quality assurance requirements of the COVID-19 diagnostic process.


Author(s):  
Talha Tiryaki ◽  
Tolga Karacan ◽  
Seyma Yesiralioglu ◽  
Eser Ozyurek ◽  
Huseyin Kiyak ◽  
...  

<p><strong>Objective:</strong> Owing to its high sensitivity and specificity, and because it is widely available, transvaginal ultrasonography is the first-line imaging test of choice used for the diagnosis of endometriosis. Ultrasonographic findings evaluated in conjunction with symptoms and signs may improve the diagnosis of endometriosis. Therefore, we hypothesized that transvaginal ultrasonography combined with physical examinations performed by physicians could predict endometriosis better in patients with symptoms suggestive of endometriosis compared with asymptomatic patients at presentation.</p><p><strong>Study Design:</strong> In this retrospective cohort study, the first subjective impression obtained from the history, physical examination, and transvaginal ultrasonography performed by the physician during the first visit in the outpatient clinic was taken into consideration. Patients who underwent surgery with the indication of ovarian mass were divided into two groups according to their admission types; symptomatic and asymptomatic.</p><p><strong>Results:</strong> The number of patients reported to have endometriosis histopathologically was 138;132 were in the premenopausal period (symptomatic group n=101, asymptomatic group n=31) and 6 were in the postmenopausal period (symptomatic group n=1, asymptomatic group n=5). The positive predictive value and positive likelihood ratio of the combination of pelvic examination and transvaginal ultrasonography in premenopausal symptomatic and asymptomatic patients, and postmenopausal symptomatic and asymptomatic patients were 97.8%, 11.5; 47.3%, 6.9; 25.0%, 4.6; and 11.1%, 2.3, respectively.</p><p><strong>Conclusion:</strong> The diagnostic performance of transvaginal ultrasonography in combination with physical examination in patients with asymptomatic endometriosis cannot reach the diagnostic accuracy of physical examination combined with transvaginal ultrasonography in patients with endometriosis who present with symptoms.</p>


2020 ◽  
pp. 12-15
Author(s):  
I. M. Hussaini ◽  
S. Gide ◽  
B. Musa ◽  
M. A. Sulaiman ◽  
A. Usman

Accurate and timely SARS-CoV-2 detection in suspected persons is crucial in the fight against its spread. Many techniques have been developed to meet up with the continuously growing demand, however some of these techniques lack the required accuracy, sensitivity and specificity. The current reference standard technique for SARS-CoV-2 detection is RT-PCR, but studies have shown that false-negative results are inevitable and data can be non-reproducible when samples and primers are not appropriately verified and validated. Droplet digital PCR (ddPCR) is a newly introduced technique that performs precise nucleic acid quantification. Researchers have evaluated the efficacy of ddPCR and the technique has shown promising results even in specimens with low viral load. ddPCR has shown increased accuracy, precision, sensitivity and specificity. Furthermore, it is less affected by annealing and amplification inhibitors. This suggests that ddPCR can be used as a complementary detection technique especially in convalescent cases.


2020 ◽  
Vol 2020 ◽  
pp. 1-5 ◽  
Author(s):  
Wei Dai ◽  
Xinmiao Chen ◽  
Xiaoting Xu ◽  
Zhefeng Leng ◽  
Wenwen Yu ◽  
...  

Objective. Coronavirus disease 2019 (COVID-19), caused by the novel coronavirus SARS-CoV-2, was first identified in December 2019 in Wuhan, China, and has since spread globally, resulting in an ongoing pandemic. However, the study of asymptomatic patients is still rare, and the understanding of its potential transmission risk is still insufficient. In this study, epidemiological investigations were conducted in the Zhejiang province to understand the epidemiology and clinical characteristics of asymptomatic patients with COVID-19. Methods. This retrospective study was carried out on 22 asymptomatic patients and 234 symptomatic patients with COVID-19 who were hospitalized in Zhejiang Duodi Hospital from January 21 to March 16, 2020. The characteristics of epidemiology, demography, clinical manifestations, and laboratory data of mild patients were compared and analyzed. Results. The median age was 28 years in asymptomatic patients and 48 years in symptomatic patients. The proportion who were female was 77.3% in asymptomatic patients and 36.3% in symptomatic patients (p<0.001). The proportion of patients with coexisting diseases was 4.5% in asymptomatic patients and 38.0% in symptomatic patients (p=0.002). The proportion of patients with increased CRP was 13.6% in the asymptomatic group and 61.1% in the symptomatic group (p<0.001). The proportion of patients received antiviral therapy was 45.5% in the asymptomatic group and 97.9% in the symptomatic group (p<0.001). The proportion of patients received oxygen therapy was 22.7% in the asymptomatic group and 99.1% in symptomatic patients (p<0.001). By March 16, 2020, all patients were discharged from the hospital, and no symptoms had appeared in the asymptomatic patients during hospitalization. The median course of infection to discharge was 21.5 days in asymptomatic patients and 22 days in symptomatic patients. Conclusions. Asymptomatic patients are also infectious; relying only on clinical symptoms, blood cell tests, and radiology examination will lead to misdiagnosis of most patients, leading to the spread of the virus. Investigation of medical history is the best strategy for screening asymptomatic patients, especially young people, women, and people without coexisting disease, who are more likely to be asymptomatic when infected. Although the prognosis is good, isolation is critical for asymptomatic patients, and it is important not to end isolation early before a nucleic acid test turns negative.


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