scholarly journals Is it enough for COVID-19 screening test? Limitation of swab test and general characteristics of mild symptom patients

2021 ◽  
Vol 104 (2) ◽  
pp. 003685042110261
Author(s):  
Sungwoo Choi ◽  
Hyo Jeong Choi ◽  
Ho Jung Kim
Keyword(s):  
Screening Test ◽  
Community Treatment ◽  
Upper Respiratory Tract ◽  
Test Results ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Positive Rate ◽  
Upper Respiratory ◽  
Polymerase Chain ◽  
Discharge Criteria

The most common method for SARS-CoV-2 testing is throat or nasal swabbing by real-time reverse transcription polymerase chain reaction (RT-PCR) assay. In South Korea, drive-through swab test is used for screening system and community treatment centers (CTCs), which admit and treat confirmed COVID-19 patients with mild symptoms, are being used. This retrospective study was conducted on patients admitted to a CTC on March 6, 2020. A total of 313 patients were admitted. The nasal and throat swabs were collected from the upper respiratory tract, and a sputum test was performed to obtain lower respiratory samples. The positive rate of the first set of test, sputum test was higher than that of the swab test ( p = 0.011). In the second set of test, 1 week after the first ones, the rate of positive swab tests was relatively high ( p = 0.026). In the first set of test, 66 of 152 (43.4%) patients showed 24-h consecutive negative swab test results, when the sputum test results were considered together, that number fell to 29 patients (19.1%) ( p < 0.001). Also, in the second set of test, 63 of 164 (38.4%) patients met the discharge criteria only when the swab test was considered; that number fell to 30 (18.3%) when the sputum test results were also considered ( p < 0.001). Using the swab test alone is insufficient for screening test and discharge decision. Patients who may have positive result in the sputum test can be missed.

scholarly journals A combined oro-nasopharyngeal swab is more sensitive than mouthwash in detecting SARS-CoV-2 by a high-throughput PCR assay

2020 ◽  
Author(s):  
Wiebke Michel ◽  
Jacqueline Farber ◽  
Milica Dilas ◽  
Ina Tammer ◽  
Jannik Baar ◽  
...  
Keyword(s):  
Respiratory Tract ◽  
Test Performance ◽  
Nasopharyngeal Swab ◽  
Virus Concentration ◽  
Upper Respiratory Tract ◽  
Sterile Water ◽  
Test Results ◽  
Pcr Assay ◽  
Previous Diagnosis ◽  
Upper Respiratory

Objectives: The optimal diagnostic specimen to detect SARS-CoV-2 by PCR in the upper respiratory tract is unclear. Mouthwash fluid has been reported as an alternative to nasopharyngeal and oropharyngeal swabs. We compared mouthwash fluid with a combined oro-nasopharyngeal swab regarding test performance. Methods: We tested asymptomatic persons with a previous diagnosis of COVID-19 and their household contacts. First, a mouthwash (gargling for at least 5 sec) with sterile water was performed. Then, with a single flocked swab the back of the throat and subsequently the nasopharynx were sampled. Samples were inactivated and analysed on a Roche cobas 6800 system with the Roche SARS-CoV-2 test. Results: Of 76 persons, 39 (51%) tested positive for SARS-CoV-2 by oro-nasopharyngeal swab. Mouthwash detected 13 (17%) of these infections but did not detect any additional infection. Samples that were positive in both tests, had lower cycle threshold (Ct)-values for oro-nasopharyngeal samples, indicating a higher virus concentration, compared to samples only positive in oro-nasopharyngeal swabs. Conclusions: Mouthwash is not as sensitive as combined oro-nasopharyngeal swab in detecting upper respiratory tract infection.

scholarly journals SARS-CoV-2 Detection in Fecal Sample from a Patient with Typical Findings of COVID-19 Pneumonia on CT but Negative to Multiple SARS-CoV-2 RT-PCR Tests on Oropharyngeal and Nasopharyngeal Swab Samples

Medicina ◽  
2021 ◽  
Vol 57 (3) ◽  
pp. 290
Author(s):  
Barbara Brogna ◽  
Carlo Brogna ◽  
Mauro Petrillo ◽  
Adriana Modestina Conte ◽  
Giulio Benincasa ◽  
...  
Keyword(s):  
Respiratory Tract ◽  
Clinical Symptoms ◽  
Nasopharyngeal Swab ◽  
Upper Respiratory Tract ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Negative Results ◽  
Upper Respiratory ◽  
Polymerase Chain ◽  
Pcr Test

Reverse transcriptase polymerase chain reaction (RT-PCR) negative results in the upper respiratory tract represent a major concern for the clinical management of coronavirus disease 2019 (COVID-19) patients. Herein, we report the case of a 43-years-old man with a strong clinical suspicion of COVID-19, who resulted in being negative to multiple severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RT-PCR tests performed on different oropharyngeal and nasopharyngeal swabs, despite serology having confirmed the presence of SARS-CoV-2 IgM. The patient underwent a chest computed tomography (CT) that showed typical imaging findings of COVID-19 pneumonia. The presence of viral SARS-CoV-2 was confirmed only by performing a SARS-CoV-2 RT-PCR test on stool. Performing of SARS-CoV-2 RT-PCR test on fecal samples can be a rapid and useful approach to confirm COVID-19 diagnosis in cases where there is an apparent discrepancy between COVID-19 clinical symptoms coupled with chest CT and SARS-CoV-2 RT-PCR tests’ results on samples from the upper respiratory tract.

scholarly journals Development of the one-step qualitative RT-PCR assay to detect SARS-CoV-2 Omicron (B.1.1.529) variant in respiratory specimens

2022 ◽  
Author(s):  
Tung Phan ◽  
Stephanie Boes ◽  
Melissa McCullough ◽  
Jamie Gribschaw ◽  
Alan Wells
Keyword(s):  
Limit Of Detection ◽  
Cross Reactivity ◽  
Upper Respiratory Tract ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Qualitative Detection ◽  
One Step ◽  
Upper Respiratory ◽  
The One ◽  
Respiratory Specimens

A new SARS-CoV-2 Omicron (B.1.1.529) Variant of Concern has been emerging worldwide. We are seeing an unprecedented surge in patients due to Omicron in this COVID-19 pandemic. A rapid and accurate molecular test that effectively differentiates Omicron from other SARS-CoV-2 variants would be important for both epidemiologic value and for directing variant-specific therapies such as monoclonal antibody infusions. In this study, we developed a real-time RT-PCR assay for the qualitative detection of Omicron from routine clinical specimens sampling the upper respiratory tract. The limit of detection of the SARS-CoV-2 Omicron variant RT-PCR assay was 2 copies/μl. Notably, the assay did not show any cross-reactivity with other SARS-CoV-2 variants including Delta (B.1.617.2). This SARS-CoV-2 Omicron variant RT-PCR laboratory-developed assay is sensitive and specific to detect Omicron in nasopharyngeal and nasal swab specimens.

scholarly journals Amplification of human β-glucoronidase gene for appraising the accuracy of negative SARS-CoV-2 RT-PCR results in upper respiratory tract specimens

2020 ◽  
Author(s):  
Eliseo Albert ◽  
Blanca Ferrer ◽  
Ignacio Torres ◽  
Alicia Serrano ◽  
Maria Jesus Alcaraz ◽  
...  
Keyword(s):  
Respiratory Tract ◽  
Operating Characteristic ◽  
False Negative ◽  
Upper Respiratory Tract ◽  
Rt Pcr ◽  
Roc Curve Analysis ◽  
True Negative ◽  
Negative Results ◽  
Upper Respiratory ◽  
Polymerase Chain

Real-time reverse transcription polymerase-chain reaction (RT-PCR) is the mainstay of Covid-19 diagnosis. False-negative RT-PCR results may hamper clinical management of patients and hinder the adoption of epidemiological measures to control the pandemic. The current study was aimed at assessing whether amplification of β-glucoronidase (GUSB) gene would help estimate the accuracy of SARS-CoV-2 RT-PCR negative results in upper respiratory tract (URT) specimens. URT specimens that tested negative by SARS-CoV-2 RT-PCR displayed higher GUSB RT-PCR cycle thresholds (CT) (P=0.070) than those testing positive (median, 30.7; range, 27.0-40.0, and median 29.7; range 25.5-36.8, respectively), this reflecting poorer cellularity. Receiver operating characteristic (roc) curve analysis indicated that a CT threshold of 31.2 discriminated best between positive and negative SARS CoV-2 RT-PCRs (area under a curve, 0.66; 95% CI, 0.50-0.81; P=0.08). This cut-off yielded a true negative ratio of 89% and accuracy of 70%. The data suggested that amplification of the GUSB gene by RT-PCR may help to appraise the accuracy of negative SARS-CoV-2 RT-PCR results in patients in whom Covid-19 is eventually diagnosed.

scholarly journals Clinical evaluation of a multiplex RT-PCR assay for detection of SARS-CoV-2 in individual and pooled upper respiratory tract samples

2021 ◽  
Author(s):  
Melissa Laverack ◽  
Rebecca L. Tallmadge ◽  
Roopa Venugopalan ◽  
Brittany Cronk ◽  
XiuLin Zhang ◽  
...  
Keyword(s):  
Clinical Evaluation ◽  
High Throughput ◽  
Predictive Value ◽  
Diagnostic Sensitivity ◽  
Analytical Sensitivity ◽  
Upper Respiratory Tract ◽  
Rt Pcr ◽  
Pcr Assay ◽  
P Gene ◽  
Upper Respiratory

Abstract The aim of this study was to identify and validate a sensitive, high-throughput and cost-effective SARS-CoV-2 RT-PCR assay to be used as a surveillance and diagnostic tool for SARS-CoV-2 in a University surveillance program. We conducted a side-by-side clinical evaluation of a newly developed SARS-CoV-2 multiplex assay (EZ-SARS-CoV-2 Real-Time RT-PCR) with the commercial TaqPath COVID-19 Combo kit, which has an Emergency Use Authorization from the FDA. The EZ-SARS-CoV-2 RT-PCR incorporates two assays targeting the SARS-CoV-2 N gene, an internal control targeting the human RNase P gene, and a PCR inhibition control in a single reaction. Nasopharyngeal (NP) and anterior nares (AN) swabs were tested as individuals and pools with both assays and in the ABI 7500 Fast and the QuantStudio 5 detection platforms. The EZ-SARS-CoV-2 RT-PCR assay analytical sensitivity was 250 copies/ml or approximately 1.75 genome copy equivalents per reaction. Clinical performance of the EZ-SARS-CoV-2 assay was determined using NP and AN samples tested in other laboratories. The diagnostic sensitivity of the assay ranged between 94 and 96% across the detection platforms, and the diagnostic specificity was 94.06%. The positive predictive value was 94% and the negative predictive value ranged from 94 to 96%. Pooling five NP or AN specimens yielded 93% diagnostic sensitivity. The overall agreement between these SARS-CoV-2 RT-PCR assays was high, supported by Cohen’s kappa value of 0.93. The EZ-SARS-CoV-2 RT-PCR assay performance attributes of high sensitivity, excellent performance in AN sample matrix and in pooled upper respiratory samples support its use in a high-throughput surveillance testing program.

scholarly journals Declining SARS-CoV-2 PCR sensitivity with time and dependence on clinical features: consequences for control

2020 ◽  
Author(s):  
Barbara J.M. Bergmans ◽  
Chantal B.E.M. Reusken ◽  
Anne J.G. Van Oudheusden ◽  
Gert-Jan Godeke ◽  
Axel A. Bonacic Marinovic ◽  
...  
Keyword(s):  
Disease Severity ◽  
Upper Respiratory Tract ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Clinical Sensitivity ◽  
Health Measures ◽  
Supportive Role ◽  
Upper Respiratory ◽  
Polymerase Chain ◽  
Bayesian Statistical Modeling

Real-time reverse transcription-polymerase chain reaction (RT-PCR) on upper respiratory tract (URT) samples is the primary method to diagnose SARS-CoV-2 infections and guide public health measures, with a supportive role for serology. However, the clinical sensitivity of RT-PCR remains uncertain. In the present study, Bayesian statistical modeling was used to retrospectively determine the sensitivity of RT-PCR using SARS-CoV-2 serology in 644 COVID-19-suspected patients with varying degrees of disease severity and duration. The sensitivity of RT-PCR ranged between 79-95%; while increasing with disease severity, it decreased rapidly over time in mild COVID-19 cases. Negative URT RT-PCR results should therefore be interpreted in the context of clinical characteristics, especially with regard to containment of viral transmission based on the 'test, trace and isolate' principle.

scholarly journals The Issue of Recurrently Positive Patients Who Recovered From COVID-19 According to the Current Discharge Criteria: Investigation of Patients from Multiple Medical Institutions in Wuhan, China

2020 ◽  
Vol 222 (11) ◽  
pp. 1784-1788 ◽  
Author(s):  
You Zou ◽  
Bin-Ru Wang ◽  
Liu Sun ◽  
Shan Xu ◽  
Yong-Gang Kong ◽  
...  
Keyword(s):  
Test Results ◽  
Rt Pcr ◽  
Chain Reaction ◽  
Current Discharge ◽  
Negative Results ◽  
Medical Institutions ◽  
Polymerase Chain ◽  
Discharge Criteria ◽  
Test Result ◽  
Pcr Test

Abstract The current discharge criteria for COVID-19 require that patients have 2 consecutive negative results for reverse transcription polymerase chain reaction (RT-PCR) detection. Here, we observed that recurrent positive RT-PCR test results in patients with 3 consecutive negative results (5.4%) were significantly decreased compared with those in patients with 2 consecutive negative results (20.6%); such patients reported positive RT-PCR test results within 1 to 12 days after meeting the discharge criteria. These results confirmed that many recovered patients could show a positive RT-PCR test result, and most of these patients could be identified by an additional RT-PCR test prior to discharge.

scholarly journals SARS-COV-2 in Ophthalmology: Current Evidence and Standards for Clinical Practice

2020 ◽  
Vol 33 (13) ◽  
Author(s):  
Sónia Torres-Costa ◽  
Mário Lima-Fontes ◽  
Fernando Falcão-Reis ◽  
Manuel Falcão
Keyword(s):  
Nasolacrimal Duct ◽  
Current Evidence ◽  
Upper Respiratory Tract ◽  
Rt Pcr ◽  
Ocular Manifestations ◽  
Protection Strategies ◽  
Positive Rate ◽  
Eye Involvement ◽  
Upper Respiratory ◽  
The Relationship

Introduction: COVID-19 is caused by the coronavirus SARS-CoV-2. Ocular manifestations have been reported including conjunctivitis and retinal changes. Therefore, it is of the utmost importance to clarify eye involvement in COVID-19 in order to help with its diagnosis and to further prevent its transmission. The purpose of this review is to describe the structure and transmission of SARS-CoV-2, reported ocular findings and protection strategies for ophthalmologists.Material and Methods: Literature search on PubMed for relevant articles using the keywords ‘COVID-19’, ‘coronavirus’, and ‘SARS-CoV-2’ in conjunction with ‘ophthalmology’ and ‘eye’. Moreover, official recommendations of ophthalmological societies were reviewed.Results: Although the conjunctiva is directly exposed to extraocular pathogens, and the mucosa of the ocular surface and upper respiratory tract are connected by the nasolacrimal duct, the eye is rarely involved in human SARS-CoV-2 infection and the SARS-CoV-2 RNA positive rate by RT-PCR test in tears and conjunctival secretions from patients with COVID-19 is also extremely low.Discussion: The eye can be affected by SARS-CoV-2, which is supported by some reports of conjunctivitis and retinal changes, but its role in the spread of the disease is still unknown.Conclusion: Given the current scarce evidence, more research is needed to clarify the relationship between SARS-CoV-2 and the eye.

scholarly journals Comparison of two commercial molecular tests and a laboratory-developed modification of the CDC 2019-nCOV RT-PCR assay for the qualitative detection of SARS-CoV-2 from upper respiratory tract specimens

2020 ◽  
Author(s):  
Nicholas M. Moore ◽  
Haiying Li ◽  
Debra Schejbal ◽  
Jennifer Lindsley ◽  
Mary K. Hayden
Keyword(s):  
Respiratory Tract ◽  
Medical Record ◽  
Medical Record Review ◽  
Nasopharyngeal Swab ◽  
Upper Respiratory Tract ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Upper Respiratory ◽  
Record Review ◽  
Swab Specimen

ABSTRACTWe compared the ability of 2 commercial molecular amplification assays [RealTime SARS-CoV-2 on the m2000 (Abbott) and ID NOW™ COVID-19 (Abbott)] and a laboratory-developed test [modified CDC 2019-nCoV RT-PCR assay with RNA extraction by eMag® (bioMérieux) and amplification on QuantStudio™ 6 or ABI 7500 Real-Time PCR System (Life Technologies)] to detect SARS-CoV-2 RNA in upper respiratory tract specimens. Discrepant results were adjudicated by medical record review. 200 nasopharyngeal swab specimens in viral transport medium (VTM) were collected from symptomatic patients between March 27 and April 9, 2020. Results were concordant for 167 specimens (83.5% overall agreement), including 94 positive and 73 negative specimens. The RealTime SARS-CoV-2 assay on the m2000 yielded 33 additional positive results, 25 of which were also positive by the modified CDC assay but not by the ID NOW™ COVID-19 assay. In a follow-up evaluation, 97 patients for whom a dry nasal swab specimen yielded negative results by the ID NOW™ COVID-19 assay had a paired nasopharyngeal swab specimen collected in VTM and tested by the RealTime SARS-CoV-2 assay; SARS-CoV-2 RNA was detected in 13 (13.4%) of these specimens. Medical record review deemed all discrepant results to be true positives. The ID NOW™ COVID-19 test was the easiest to perform and provided a result in the shortest time: as soon as 5 minutes for positive and 13 minutes for negative result. The RealTime SARS-CoV-2 assay on the m2000 detected more cases of COVID-19 infection than the modified CDC assay or the ID NOW™ COVID-19 test.

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