scholarly journals Sensitivity and Specificity of Lateral Flow Antigen Test Kits for COVID-19 in Asymptomatic Population of Quarantine Centre of Province 3

2020 ◽  
Vol 18 (2) ◽  
pp. 36-39
Author(s):  
B. Shrestha ◽  
A.K. Neupane ◽  
S. Pant ◽  
A. Shrestha ◽  
A. Bastola ◽  
...  

Background Nearly after 6 months of the spread of Corona Virus Disease 19, along with the world Nepal is still trying to control the spread and prevent general population from acquiring it. With limited resources in manpower, technology and evidence it has been a difficult battle. But with time and more understanding of the virus new technology to detect the virus are coming up. It is a major breakthrough in the diagnostic field as this helps us in not only detecting the virus but also helps us to mobilize our human resources. This comes in a time where the cases are increasing at an alarming rate. Although numbers of Polymerase Chain Reaction testing have increased but due to the time consuming and the cost wise, we need a faster and equally reliable alternative. Antigen test approved by different countries can be used for point of care, screening and surveillance depending upon the requirements after calculating its sensitivity, specificity and accuracy. Objective To find out sensitivity and specificity of the Antigen test kit for COVID-19. Method Antigen tests were compared with Reverse Transcription Polymerase Chain Reaction as a reference standard in calculated sample size of 113 subjects in a high risk population. Both Reverse Transcription Polymerase Chain Reaction and antigen test were performed in a same subject with in maximum of 2 days’ interval. Convenience sampling technique was used to select the subjects. Ethical approval was taken from Nepal Health Research Council before data collection. Study was done from August to September 2020 from Quarantine center of Province 3. Result There were total of 113 test carried out, among those 47 were positive and 66 were negative in Reverse Transcription Polymerase Chain Reaction. After preparing two by two table, Sensitivity and specificity of the tested was calculated which came out to be 85% and 100% respectively, with accuracy of 93.80%. Conclusion Even though the sensitivity and specificity came to be higher, this test should be interpreted cautiously depending upon the prevalence of Corona Virus Disease 19 in that particular community and the clinical and epidemiological context of the person who has been tested. When in doubt by clinical correlation should be confirmed with Reverse Transcription Polymerase Chain Reaction.

2020 ◽  
Vol 18 (1) ◽  
pp. 74-77
Author(s):  
Shyam Kumar BK ◽  
Sumit Pandey ◽  
Nabin Poudel ◽  
Sandesh Pandit ◽  
Alok Kumar Sah ◽  
...  

Introduction: At the end of 2019 a novel virus, named SARS-CoV-2 (Severe Acute Respiratory Syndrome Coronavirus 2), expanded globally from China. A new coronavirus, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), was identified as the cause of this outbreak of viral pneumonia that causes coronavirus disease 2019 (COVID-19). Aims: The aim of this study is to find out the chest radiological features of corona virus disease patients and correlate them with clinical outcome. Methods: This is a Hospital based study involving patients with clinical-epidemiological aspect of all reverse transcription polymerase chain reaction (RT-PCR) corona virus disease (COVID-19) positive patients, who performed Chest X-Rays at the emergency department of Nepalgunj Medical College, Teaching Hospital from March to June, 2020. All patients performed reverse transcription polymerase chain reaction from nasopharyngeal and throat swab, Chest X-Ray at the Emergency Department and clinical-epidemiological data. Results: Patients with a reverse transcription polymerase chain reaction positive results for corona virus disease infection were 32 out of these, 22 were females (68.75%) and 10 males (31.25%), with a mean age of 40.78 years (range 20–74 years). Only 2 Chest X-Rays were negative for radiological thoracic involvement (6.25%).  The following alterations were more commonly observed among 30 patients: 18 patients with lung consolidations (56.25%), 19 (59.37%) with Ground Glass Opacities, 7 (21.87%) with nodules and 21 (65.6%) with reticular–nodular opacities. Patients with consolidations and Ground Glass Opacities coexisting in the same radiography were 34.37% of total. In reverse transcription polymerase chain reaction positive patients, we found also signs nonspecific for corona virus disease pneumonia as hilar or vascular congestion (37.5%), cardiomegaly (28.12%), pleural effusion (15.6%) and pneumothorax (3.12%). Peripheral (56.25%) and lower zone distribution (56.25%) were the most common predominance. Bilateral involvement (68.75%) was most frequent than unilateral one. Given the results, baseline Chest X-Rays sensitivity in our experience is about 65.62%. Conclusion: In this study, COVID-19 CXRs generally manifested a spectrum of pure ground glass, mixed ground glass opacities to consolidation in bilateral peripheral middle and lower lung zones. BSTI CXR reporting classification of COVID-19 is valid and sensitive in our patients with addition of middle zonal involvement in classical COVID-19 criteria as opposed to just lower zone involvement.


2021 ◽  
Vol 8 ◽  
Author(s):  
Kate Hole ◽  
Charles Nfon ◽  
Luis L. Rodriguez ◽  
Lauro Velazquez-Salinas

Vesicular stomatitis virus (VSV) causes a disease in susceptible livestock that is clinically indistinguishable from foot-and-mouth disease. Rapid testing is therefore critical to identify VSV and rule out FMD. We previously developed and validated a multiplex real-time reverse transcription polymerase chain reaction assay (mRRT-PCR) for detection of both VS New Jersey virus (VSNJV) and VS Indiana virus (VSIV). However, it was subsequently apparent that this assay failed to detect some VSNJV isolates in Mexico, especially in genetic group II, lineage 2.1. In order to enhance the sensitivity of the mRRT-PCR for VSNJV, parts of the assay were redesigned and revalidated using new and improved PCR chemistries. The redesign markedly improved the assay by increasing the VSNJV detection sensitivity of lineage 2.1 and thereby allowing detection of all VSNJV clades. The new assay showed an increased capability to detect VSNJV. Specifically, the new mRRT-PCR detected VSNJV in 100% (87/87) of samples from Mexico in 2006-2007 compared to 74% for the previous mRRT-PCR. Furthermore, the analytical sensitivity of the new mRRT-PCR was enhanced for VSNJV. Importantly, the modified assay had the same sensitivity and specificity for VSIV as the previously published assay. Our results highlight the challenges the large genetic variability of VSV pose for virus detection by mRRT-PCR and show the importance of frequent re-evaluation and validation of diagnostic assays for VSV to ensure high sensitivity and specificity.


1999 ◽  
Vol 123 (12) ◽  
pp. 1161-1169 ◽  
Author(s):  
JoséR. Romero

Abstract Objective.—This review focuses on commercial and in-house–developed reverse-transcription polymerase chain reaction (RT-PCR) assays used for the detection of enteroviral infections. In addition to providing details on the performance of RT-PCR, its specificity, and sensitivity, the clinical utility of this diagnostic method with specific reference to its impact on hospitalization and cost savings is addressed. Data Sources.—MEDLINE was searched for reports relating to RT-PCR detection of the enteroviruses in adults and children. The search was restricted to studies reported in English language journals. Study Selection.—Reports documenting detailed information regarding the RT-PCR conditions, primers, sensitivity, specificity and, if relevant, clinical impact were selected for analysis. Data Extraction.—Details regarding method of extraction of the enteroviral genome, the primers used, RT-PCR conditions, and sensitivity and specificity of the assay were extracted from the literature. For reports detailing the use of RT-PCR in the clinical management of enteroviral infections in children, the reduction in duration of hospitalization and health care cost savings were recorded. Data Synthesis.—Reverse-transcription PCR can increase the yield of detection of enteroviruses from cerebrospinal fluid by a mean of approximately 20% over tissue culture. Reverse-transcription PCR of cerebrospinal fluid has been shown to exhibit sensitivity and specificity values of 86% to 100% and 92% to 100%, respectively. Reductions of 1 to 3 days of hospitalization per patient are predicted if RT-PCR is used to diagnose enteroviral meningitis in children. Conclusions.—Reverse-transcription PCR detection of enteroviral infections is an extremely rapid, sensitive, and specific diagnostic modality. Both commercial assays and assays developed in-house appear to be equivalent with regard to sensitivity and specificity. Reverse-transcription PCR diagnosis of enteroviral infections in children could reduce the length of hospitalization and result in significant health care cost savings.


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