scholarly journals Evaluation of SARS-CoV-2 Antigen-Based Rapid Diagnostic Kits in Pakistan: Formulation of COVID-19 National Testing Strategy.

2020 ◽  
Author(s):  
Umar Saeed ◽  
Sara Rizwan Uppal ◽  
Zahra Zahid Piracha ◽  
Azhar Rasheed ◽  
Zubair Aftab ◽  
...  
Keyword(s):  
Gold Standard ◽  
Injection Drug Users ◽  
Drug Users ◽  
Diagnostic Testing ◽  
False Negative ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Cross Sectional ◽  
Negative Results ◽  
Treatment And Prevention

Abstract Rapid diagnosis of SARS-CoV-2 during pandemic enables timely treatment and prevention of COVID-19. Evaluating the accuracy and reliability of rapid diagnostic testing kits is crucial for surveillance and diagnosis of SARS-CoV-2 infections in general population, injection drug users, multi-transfused populations, healthcare workers, prisoners, barbers and other high risk populations. The aim of this study was to evaluate performance and effectiveness of nasopharyngeal swab (NSP) and saliva based rapid antigen detection testing kits in comparison with USFDA approved triple target gold standard real-time polymerase chain reaction. A cross-sectional sectional study was conducted on 33,000 COVID-19 suspected patients. From RT-PCR positive patients, nasopharyngeal swab (NSP) and saliva samples were obtained for evaluation of rapid COVID-19 testing kits (RDT). 100/33000 (0.3%) of specimens were RT-PCR positive for SARS-CoV-2. Among RT-PCR positive, 62% were males, 34% were females, and 4% were children. The NSP-RDT (Lepu Medical China) analysis revealed 53% reactivity among males, 58% reactivity among females, and 25% reactivity among children. However saliva based RDT (Lepu Medical China) analysis showed 21% reactivity among males and 23% among females, and no reactivity in children. False negative results were significantly more pronounced in saliva based RDT as compared to NSP-RDT. The sensitivity of these NSP-RDT and saliva based RDT were 52% and 21% respectively. The RDTs evaluated in this study showed limited sensitivities in comparison to gold standard RT-PCR, indicating that there is a dire need in Pakistan for development of suitable testing to improve accurate COVID-19 diagnosis in line with national demands.

scholarly journals Evaluation of SARS-CoV-2 antigen-based rapid diagnostic kits in Pakistan: formulation of COVID-19 national testing strategy

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Umar Saeed ◽  
Sara Rizwan Uppal ◽  
Zahra Zahid Piracha ◽  
Azhar Rasheed ◽  
Zubair Aftab ◽  
...  
Keyword(s):  
Gold Standard ◽  
Injection Drug Users ◽  
Drug Users ◽  
Diagnostic Testing ◽  
False Negative ◽  
Cross Sectional Study ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Cross Sectional ◽  
Negative Results

AbstractRapid diagnosis of SARS-CoV-2 during pandemic enables timely treatment and prevention of COVID-19. Evaluating the accuracy and reliability of rapid diagnostic testing kits is crucial for surveillance and diagnosis of SARS-CoV-2 infections in general population, injection drug users, multi-transfused populations, healthcare workers, prisoners, barbers and other high risk populations. The aim of this study was to evaluate performance and effectiveness of nasopharyngeal swab (NSP) and saliva based rapid antigen detection testing kits in comparison with USFDA approved triple target gold standard real-time polymerase chain reaction. A cross-sectional study was conducted on 33,000 COVID-19 suspected patients. From RT-PCR positive patients, nasopharyngeal swab (NSP) and saliva samples were obtained for evaluation of rapid COVID-19 testing kits (RDT). 100/33,000 (0.3%) of specimens were RT-PCR positive for SARS-CoV-2. Among RT-PCR positive, 62% were males, 34% were females, and 4% were children. The NSP-RDT (Lepu Medical China) analysis revealed 53% reactivity among males, 58% reactivity among females, and 25% reactivity among children. However saliva based RDT (Lepu Medical China) analysis showed 21% reactivity among males and 23% among females, and no reactivity in children. False negative results were significantly more pronounced in saliva based RDT as compared to NSP-RDT. The sensitivity of these NSP-RDT and saliva based RDT were 52% and 21% respectively. The RDTs evaluated in this study showed limited sensitivities in comparison to gold standard RT-PCR, indicating that there is a dire need in Pakistan for development of suitable testing to improve accurate COVID-19 diagnosis in line with national demands.

scholarly journals Evaluation of SARS-CoV-2 antigen-based rapid diagnostic kits in Pakistan: formulation of COVID-19 national testing strategy.

2021 ◽  
Author(s):  
Umar Saeed ◽  
Sara Rizwan Uppal ◽  
Zahra Zahid Piracha ◽  
Azhar Rasheed ◽  
Zubair Aftab ◽  
...  
Keyword(s):  
Gold Standard ◽  
Injection Drug Users ◽  
Drug Users ◽  
Diagnostic Testing ◽  
False Negative ◽  
Cross Sectional Study ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Cross Sectional ◽  
Negative Results

Abstract Rapid diagnosis of SARS-CoV-2 during pandemic enables timely treatment and prevention of COVID-19. Evaluating the accuracy and reliability of rapid diagnostic testing kits is crucial for surveillance and diagnosis of SARS-CoV-2 infections in general population, injection drug users, multi-transfused populations, healthcare workers, prisoners, barbers and other high risk populations. The aim of this study was to evaluate performance and effectiveness of nasopharyngeal swab (NSP) and saliva based rapid antigen detection testing kits in comparison with USFDA approved triple target gold standard real-time polymerase chain reaction. A cross-sectional study was conducted on 33,000 COVID-19 suspected patients. From RT-PCR positive patients, nasopharyngeal swab (NSP) and saliva samples were obtained for evaluation of rapid COVID-19 testing kits (RDT). 100/33000 (0.3%) of specimens were RT-PCR positive for SARS-CoV-2. Among RT-PCR positive, 62% were males, 34% were females, and 4% were children. The NSP-RDT (Lepu Medical China) analysis revealed 53% reactivity among males, 58% reactivity among females, and 25% reactivity among children. However saliva based RDT (Lepu Medical China) analysis showed 21% reactivity among males and 23% among females, and no reactivity in children. False negative results were significantly more pronounced in saliva based RDT as compared to NSP-RDT. The sensitivity of these NSP-RDT and saliva based RDT were 52% and 21% respectively. The RDTs evaluated in this study showed limited sensitivities in comparison to gold standard RT-PCR, indicating that there is a dire need in Pakistan for development of suitable testing to improve accurate COVID-19 diagnosis in line with national demands.

Scoring System for the Diagnosis of COVID-19

2020 ◽  
Vol 13 (1) ◽  
pp. 413-414 ◽  
Author(s):  
Mohamed Farouk Allam
Keyword(s):  
Scoring System ◽  
Clinical Symptoms ◽  
False Negative ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Negative Results ◽  
False Negative Results ◽  
Symptoms And Signs

Due to the international spread of COVID-19, the difficulty of collecting nasopharyngeal swab specimen from all suspected patients, the costs of RT-PCR and CT, and the false negative results of RT-PCR assay in 41% of COVID-19 patients, a scoring system is needed to classify the suspected patients in order to determine the need for follow-up, home isolation, quarantine or the conduction of further investigations. A scoring system is proposed as a diagnostic tool for suspected patients. It includes Epidemiological Evidence of Exposure, Clinical Symptoms and Signs, and Investigations (if available). This scoring system is simple, could be calculated in a few minutes, and incorporates the main possible data/findings of any patient.

scholarly journals Superiority of MALDI-TOF Mass Spectrometry over Real-Time PCR for SARS-CoV-2 RNA Detection

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 730
Author(s):  
Magda Rybicka ◽  
Ewa Miłosz ◽  
Krzysztof Piotr Bielawski
Keyword(s):  
Mass Spectrometry ◽  
Gold Standard ◽  
Viral Genome ◽  
False Negative ◽  
Rt Pcr ◽  
Rna Detection ◽  
Maldi Tof ◽  
Negative Results ◽  
False Negative Results ◽  
Pcr Test

At present, the RT-PCR test remains the gold standard for early diagnosis of SARS-CoV-2. Nevertheless, there is growing evidence demonstrating that this technique may generate false-negative results. Here, we aimed to compare the new mass spectrometry-based assay MassARRAY® SARS-CoV-2 Panel with the RT-PCR diagnostic test approved for clinical use. The study group consisted of 168 suspected patients with symptoms of a respiratory infection. After simultaneous analysis by RT-PCR and mass spectrometry methods, we obtained discordant results for 17 samples (10.12%). Within fifteen samples officially reported as presumptive positive, 13 were positive according to the MS-based assay. Moreover, four samples reported by the officially approved RT-PCR as negative were positive in at least one MS assay. We have successfully demonstrated superior sensitivity of the MS-based assay in SARS-CoV-2 detection, showing that MALDI-TOF MS seems to be ideal for the detection as well as discrimination of mutations within the viral genome.

scholarly journals Effectivity Analysis of SARS-CoV-2 Nasopharyngeal Swab Rapid Testing Kits in Pakistan: A Scenario of Inadequate COVID-19 Diagnosis

2021 ◽  
Author(s):  
Umar Saeed ◽  
Sara Rizwan Uppal ◽  
Zahra Zahid Piracha ◽  
Aftab Ahmad Khan ◽  
Azhar Rasheed ◽  
...  
Keyword(s):  
Gold Standard ◽  
Rapid Detection ◽  
International Health ◽  
Time Frame ◽  
Cross Sectional Study ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Cross Sectional ◽  
International Health Organizations ◽  
Polymerase Chain

Abstract COVID-19 pandemic has urged the need of rapid detection of SARS-CoV-2 in limited time frame. To cope with current, COVID-19 expanding scenario, accurate diagnosis of SARS-CoV-2 should be ensured by both national and international health organizations. Sporadic marketing of SARS-CoV-2 rapid detection kits raises questions regarding quality control and assurance. To aim of this study was to examine the effectiveness of SARS-CoV-2 nasopharyngeal swab based rapid detection kits, in comparison to gold standard USFDA approved triple target real-time polymerase chain reaction. A cross-sectional study of 1500 suspected COVID-19 patients was conducted. 100 RT-PCR confirmed patients nasopharyngeal swabs were evaluated for RDT. The COVID-19/SARS-CoV-2 NSP based RDT analysis showed 78% reactivity. Among RT-PCR confirmed negative subjects, 49.3% showed false positivity. The positive predictive analysis revealed 67.82% values, while the negative predictive vales of were 64.40%. The NSP RDTs showed limited sensitivities and specificities compared to gold standard RT-PCR. Accurate surveillance of COVID-19 is dependent upon authentic and validated SARS-CoV-2 detection nation-wide, which needs to be monitored by higher authorities. This study is critical for designing adequate measures by several COVID-19 strategic organizations to prevent future viral epidemics.

scholarly journals False-Negative Nasopharyngeal Swab RT-PCR Assays in Typical COVID-19: Role of Ultra-low-dose Chest CT and Bronchoscopy in Diagnosis

2020 ◽  
Author(s):  
Marco Marando ◽  
Adriana Tamburello ◽  
Pietro Gianella
Keyword(s):  
Low Dose ◽  
False Negative ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Oral Swab ◽  
Negative Results ◽  
False Negative Results ◽  
Polymerase Chain ◽  
Pcr Assays

On 11 March 2020, the WHO declared COVID-19 a pandemic and global health emergency. We describe the clinical features and role of ultra-low-dose chest computed tomography (CT) and bronchoscopy in the diagnosis of coronavirus disease (COVID-19). In our patient, who was highly suggestive clinically and radiologically for COVID-19, we had two false-negative results for nasopharyngeal and oral swab reverse-transcriptase polymerase chain reaction (RT-PCR) assays for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Eventually, we confirmed the diagnosis using bronchoscopy and bronchoalveolar lavage (BAL).

scholarly journals More Accurate Estimates of the Accuracy of RT-PCR and Chest CT Tests for COVID-19

2021 ◽  
Author(s):  
Lu Wang ◽  
Xueqing Liu ◽  
Chen Xia ◽  
Jun Liu ◽  
Xiao-Hua Zhou
Keyword(s):  
Gold Standard ◽  
False Negative ◽  
Chest Ct ◽  
Rt Pcr ◽  
Original Population ◽  
Verification Bias ◽  
Negative Results ◽  
False Negative Results ◽  
Lower Specificity ◽  
Pcr Test

Abstract In this article, we propose a novel statistical method for estimating the accuracy of chest computed tomography (CT) and reverse transcription polymerase chain reaction (RT-PCR) tests in the diagnosis of coronavirus disease 2019 (COVID-19), with a correction for imperfect gold standard and verification bias simultaneously. These two types of bias are often involved in estimating the diagnostic accuracy of COVID-19 tests. Imperfect gold standard bias arises when estimating accuracy measures of chest CT while using the RT-PCR test as a gold standard, despite its tendency to produce false negative results. Meanwhile, verification bias occurs in some studies where the results from chest CT are verified by RT-PCR test in a subsample of suspected cases that is not representative of the original population. Consequently, the accuracy estimates of chest CT and RT-PCR tests could be seriously biased and lead to invalid inference. Our proposed method is able to correct these two types of bias in providing unbiased and more accurate estimates of sensitivity and specificity of the two tests. Our results suggest that chest CT has higher sensitivity and lower specificity than RT-PCR, and the accuracy estimates can serve as an important reference for assessing and comparing the performance of these two tests in the diagnosis of COVID-19, and could guide policy recommendations for the implementation of these tests.

scholarly journals Lumipulse G SARS-CoV-2 Ag Assay Evaluation for SARS-CoV-2 Antigen Detection Using 594 Nasopharyngeal Swab Samples from Different Testing Groups

2021 ◽  
Author(s):  
Giulia Menchinelli ◽  
Licia Bordi ◽  
Flora Marzia Liotti ◽  
Ivana Palucci ◽  
Maria Rosaria Capobianchi ◽  
...  
Keyword(s):  
Positive Result ◽  
Limit Of Detection ◽  
False Negative ◽  
Antigen Detection ◽  
Nasopharyngeal Swab ◽  
Repeated Testing ◽  
Rt Pcr ◽  
Subgenomic Rna ◽  
Negative Results ◽  
Percent Agreement

ABSTRACTCompared to RT-PCR, lower performance of antigen detection assays, including the Lumipulse G SARS-CoV-2 Ag assay, may depend on specific testing scenarios. We tested 594 nasopharyngeal swab samples from individuals with COVID-19 (RT-PCR cycle threshold [Ct] values ≤40) or non-COVID-19 (Ct values ≤40) diagnoses. RT-PCR positive samples were assigned to diagnostic, screening, or monitoring groups of testing. With a limit of detection of 1.2 × 104 SARS-CoV-2 RNA copies/ml, Lumipulse showed positive percent agreement (PPA) of 79.9% (155/194) and negative percent agreement of 99.3% (397/400), whereas PPAs were 100% for samples with Ct values of <18 or 18–<25 and 92.5% for samples with Ct values of 25–<30. By three groups, Lumipulse showed PPA of 87.0% (60/69), 81.1% (43/53), or 72.2% (52/72), respectively, whereas PPA was 100% for samples with Ct values of <18 or 18–<25, and was 94.4%, 80.0%, or 100% for samples with Ct values of 25–<30, respectively. RT-PCR positive samples were also tested for SARS-CoV-2 subgenomic RNA and, by three groups, testing showed that PPA was 63.8% (44/69), 62.3% (33/53), or 33.3% (24/72), respectively. PPAs dropped to 55.6%, 20.0%, or 41.7% for samples with Ct values of 25–<30, respectively. All 101 samples with a subgenomic RNA positive result had a Lumipulse assay’s antigen positive result, whereas only 54 (58.1%) of remaining 93 samples had a Lumipulse assay’s antigen positive result. In conclusion, Lumipulse assay was highly sensitive in samples with low RT-PCR Ct values, implying repeated testing to reduce consequences of false-negative results.

scholarly journals COVID-19: Test, Test and Test

2020 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Fatima A Saleh ◽  
Aleen Sleem
Keyword(s):  
Diagnostic Testing ◽  
False Negative ◽  
Detection Methods ◽  
Nucleic Acid Detection ◽  
Rt Pcr ◽  
Negative Results ◽  
Immunological Tests ◽  
False Negative Results ◽  
Different Types ◽  
Polymerase Chain

A new virus was identified in late December 2019 when China reported the first cases of pneumonia in Wuhan, and a global COVID-19 pandemic followed. The world was not late to respond, with a number of sweeping measures ranging from social distancing protocols, stringent hygienic practices, and nation-wide lockdowns, as well as COVID-19 testing campaigns in an attempt to prevent the transmission of the disease and contain the pandemic. Currently, different types of diagnostic testing have been adopted globally, such as nucleic acid detection tests, immunological tests and imaging approaches; however, real-time reverse transcriptase–polymerase chain reaction (RT-PCR) remains the “gold standard” for detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Pre-analytical factors, such as specimen selection and collection, are crucial for RT-PCR, and any suboptimal collection may contribute to false-negative results. Herein, we address some of the specimen types that have been used in molecular detection methods for COVID-19. However, the pandemic is still evolving, and information might change as more studies are conducted.

scholarly journals Lumipulse G SARS-CoV-2 Ag assay evaluation using clinical samples from different testing groups

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Giulia Menchinelli ◽  
Licia Bordi ◽  
Flora Marzia Liotti ◽  
Ivana Palucci ◽  
Maria Rosaria Capobianchi ◽  
...  
Keyword(s):  
Positive Result ◽  
Limit Of Detection ◽  
False Negative ◽  
Clinical Samples ◽  
Nasopharyngeal Swab ◽  
Repeated Testing ◽  
Rt Pcr ◽  
Subgenomic Rna ◽  
Negative Results ◽  
Percent Agreement

Abstract Objectives Compared to RT-PCR, lower performance of antigen detection assays, including the Lumipulse G SARS-CoV-2 Ag assay, may depend on specific testing scenarios. Methods We tested 594 nasopharyngeal swab samples from individuals with COVID-19 (RT-PCR cycle threshold [Ct] values ≤ 40) or non-COVID-19 (Ct values > 40) diagnoses. RT-PCR positive samples were assigned to diagnostic, screening, or monitoring groups of testing. Results With a limit of detection of 1.2 × 104 SARS-CoV-2 RNA copies/ml, Lumipulse showed positive percent agreement (PPA) of 79.9% (155/194) and negative percent agreement of 99.3% (397/400), whereas PPAs were 100% for samples with Ct values of <18 or 18–<25 and 92.5% for samples with Ct values of 25–<30. By three groups, Lumipulse showed PPA of 87.0% (60/69), 81.1% (43/53), or 72.2% (52/72), respectively, whereas PPA was 100% for samples with Ct values of <18 or 18–<25, and was 94.4, 80.0, or 100% for samples with Ct values of 25–<30, respectively. Additional testing of RT-PCR positive samples for SARS-CoV-2 subgenomic RNA showed that, by three groups, PPA was 63.8% (44/69), 62.3% (33/53), or 33.3% (24/72), respectively. PPAs dropped to 55.6, 20.0, or 41.7% for samples with Ct values of 25–<30, respectively. All 101 samples with a subgenomic RNA positive result had a Lumipulse assay’s antigen positive result, whereas only 54 (58.1%) of remaining 93 samples had a Lumipulse assay’s antigen positive result. Conclusions Lumipulse assay was highly sensitive in samples with low RT-PCR Ct values, implying repeated testing to reduce consequences of false-negative results.

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