scholarly journals Efficacy of Fluorecare SARS-CoV-2 Spike Protein Test Kit for SARS-CoV-2 detection in nasopharyngeal samples of 121 individuals working in a manufacturing company

PLoS ONE ◽  
2022 ◽  
Vol 17 (1) ◽  
pp. e0262174
Author(s):  
Valentina Tonelotto ◽  
Annamaria Davini ◽  
Laura Cardarelli ◽  
Milena Calderone ◽  
Paola Marin
Keyword(s):  
Sensitivity And Specificity ◽  
Task Force ◽  
False Negative ◽  
Real Life ◽  
Health Surveillance ◽  
Spike Protein ◽  
Rt Pcr ◽  
Test Kit ◽  
Local Company ◽  
Mean Sensitivity

Objectives The aim of this study was to evaluate the clinical performance of the Fluorecare SARS-CoV-2 Spike Protein Test Kit, a rapid immunochromatographic assay for SARS-CoV-2 detection. Moreover, we sought to point out the strategy adopted by a local company to lift the lockdown without leading to an increase in the number of COVID-19 cases, by performing a precise and timely health surveillance. Methods The rapid Fluorecare SARS-CoV-2 Spike Protein Test was performed immediately after sampling following the manufacturer’s instructions. RT-PCRs were performed within 24 hours of specimen collection. A total amount of 253 nasopharyngeal samples from 121 individuals were collected between March 16 and April 2, 2021 and tested. Results Of 253 nasopharyngeal samples, 11 (9.1%) were positive and 242 (90.9%) were negative for SARS-CoV-2 RNA by RT-PCR assays. The rapid SARS-CoV-2 antigen detection test’s mean sensitivity and specificity were 84,6% (95% CI, 54.6–98.1%) and 100% (95% CI, 98.6–100%), respectively. Two false negative test results were obtained from samples with high RT-PCR cycle threshold (Ct). Conclusion Our study suggested that Fluorecare SARS-CoV-2 Spike Protein Test can be introduced into daily diagnostic practice, as its mean sensitivity and specificity follow the standards recommended by WHO and IFCC Task Force. In addition, we underlined how the strategy adopted by a local company to risk assessment and health surveillance was appropriate for infection containment. This real-life scenario gave us the possibility to experience potential approaches aimed to preserve public health and work activities.

scholarly journals Rapid SARS-CoV-2 antigen detection assay in comparison with real-time RT-PCR assay for laboratory diagnosis of COVID-19 in Thailand

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Chutikarn Chaimayo ◽  
Bualan Kaewnaphan ◽  
Nattaya Tanlieng ◽  
Niracha Athipanyasilp ◽  
Rujipas Sirijatuphat ◽  
...  
Keyword(s):  
Real Time ◽  
Sensitivity And Specificity ◽  
False Negative ◽  
Laboratory Diagnosis ◽  
Antigen Detection ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Screening Assay ◽  
The Real ◽  
Pcr Test

Abstract Background The Coronavirus disease 2019 (COVID-19) pandemic continues to spread across the world. Hence, there is an urgent need for rapid, simple, and accurate tests to diagnose severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Performance characteristics of the rapid SARS-CoV-2 antigen detection test should be evaluated and compared with the gold standard real-time reverse transcription-polymerase chain reaction (RT-PCR) test for diagnosis of COVID-19 cases. Methods The rapid SARS-CoV-2 antigen detection test, Standard™ Q COVID-19 Ag kit (SD Biosensor®, Republic of Korea), was compared with the real-time RT-PCR test, Allplex™ 2019-nCoV Assay (Seegene®, Korea) for detection of SARS-CoV-2 in respiratory specimens. Four hundred fifty-four respiratory samples (mainly nasopharyngeal and throat swabs) were obtained from COVID-19 suspected cases and contact individuals, including pre-operative patients at Siriraj Hospital, Bangkok, Thailand during March–May 2020. Results Of 454 respiratory samples, 60 (13.2%) were positive, and 394 (86.8%) were negative for SARS-CoV-2 RNA by real-time RT-PCR assay. The duration from onset to laboratory test in COVID-19 suspected cases and contact individuals ranged from 0 to 14 days with a median of 3 days. The rapid SARS-CoV-2 antigen detection test’s sensitivity and specificity were 98.33% (95% CI, 91.06–99.96%) and 98.73% (95% CI, 97.06–99.59%), respectively. One false negative test result was from a sample with a high real-time RT-PCR cycle threshold (Ct), while five false positive test results were from specimens of pre-operative patients. Conclusions The rapid assay for SARS-CoV-2 antigen detection showed comparable sensitivity and specificity with the real-time RT-PCR assay. Thus, there is a potential use of this rapid and simple SARS-CoV-2 antigen detection test as a screening assay.

scholarly journals Real-life clinical sensitivity of SARS-CoV-2 RT-PCR test in symptomatic patients

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0251661
Author(s):  
Elisa Kortela ◽  
Vesa Kirjavainen ◽  
Maarit J. Ahava ◽  
Suvi T. Jokiranta ◽  
Anna But ◽  
...  
Keyword(s):  
Clinical Decision Making ◽  
False Negative ◽  
Real Life ◽  
Clinical Decision ◽  
Population Based ◽  
Clinical Suspicion ◽  
Rt Pcr ◽  
Clinical Sensitivity ◽  
High Clinical Suspicion ◽  
Pcr Test

Background Understanding the false negative rates of SARS-CoV-2 RT-PCR testing is pivotal for the management of the COVID-19 pandemic and it has implications for patient management. Our aim was to determine the real-life clinical sensitivity of SARS-CoV-2 RT-PCR. Methods This population-based retrospective study was conducted in March–April 2020 in the Helsinki Capital Region, Finland. Adults who were clinically suspected of SARS-CoV-2 infection and underwent SARS-CoV-2 RT-PCR testing, with sufficient data in their medical records for grading of clinical suspicion were eligible. In addition to examining the first RT-PCR test of repeat-tested individuals, we also used high clinical suspicion for COVID-19 as the reference standard for calculating the sensitivity of SARS-CoV-2 RT-PCR. Results All 1,194 inpatients (mean [SD] age, 63.2 [18.3] years; 45.2% women) admitted to COVID-19 cohort wards during the study period were included. The outpatient cohort of 1,814 individuals (mean [SD] age, 45.4 [17.2] years; 69.1% women) was sampled from epidemiological line lists by systematic quasi-random sampling. The sensitivity (95% CI) for laboratory confirmed cases (repeat-tested patients) was 85.7% (81.5–89.1%) inpatients; 95.5% (92.2–97.5%) outpatients, 89.9% (88.2–92.1%) all. When also patients that were graded as high suspicion but never tested positive were included in the denominator, the sensitivity (95% CI) was: 67.5% (62.9–71.9%) inpatients; 34.9% (31.4–38.5%) outpatients; 47.3% (44.4–50.3%) all. Conclusions The clinical sensitivity of SARS-CoV-2 RT-PCR testing was only moderate at best. The relatively high false negative rates of SARS-CoV-2 RT-PCR testing need to be accounted for in clinical decision making, epidemiological interpretations, and when using RT-PCR as a reference for other tests.

scholarly journals Real-life clinical sensitivity of SARS-CoV-2 RT-PCR test in symptomatic patients

2020 ◽  
Author(s):  
Elisa Kortela ◽  
Vesa Kirjavainen ◽  
Maarit J. Ahava ◽  
Suvi T. Jokiranta ◽  
Anna But ◽  
...  
Keyword(s):  
Clinical Decision Making ◽  
False Negative ◽  
Real Life ◽  
Clinical Decision ◽  
Population Based ◽  
Clinical Suspicion ◽  
Rt Pcr ◽  
Clinical Sensitivity ◽  
High Clinical Suspicion ◽  
Pcr Test

AbstractImportanceUnderstanding the false negative rates of SARS-CoV-2 RT-PCR testing is pivotal for the management of the COVID-19 pandemic and it has practical implications for patient management in healthcare facilities.ObjectiveTo determine the real-life clinical sensitivity of SARS-CoV-2 RT-PCR testing.DesignA retrospective study on case series from 4 March – 15 April 2020.SettingA population-based study conducted in primary and tertiary care in the Helsinki Capital Region, Finland.ParticipantsAdults who were clinically suspected of SARS-CoV-2 infection and underwent SARS-CoV-2 RT-PCR testing, and who had sufficient data for grading of clinical suspicion of COVID-19 in their medical records were eligible. All 1,194 inpatients admitted to COVID-19 cohort wards during the study period were included. The outpatient cohort of 1,814 individuals was sampled from epidemiological line lists by systematic quasi-random sampling. Altogether 83 eligible outpatients (4.6%) and 3 inpatients (0.3%) were excluded due to insufficient data for grading of clinical suspicion.ExposuresHigh clinical suspicion for COVID-19 was used as the reference standard for the RT-PCR test. Patients were considered to have high clinical suspicion of COVID-19 if the physician in charge recorded the suspicion on clinical grounds, or the patient fulfilled specifically defined clinical and exposure criteria.Main measuresSensitivity of SARS-CoV-2 RT-PCR by using manually curated clinical characteristics as the gold standard.ResultsThe study population included 1,814 outpatients (mean [SD] age, 45.4 [17.2] years; 69.1% women) and 1,194 inpatients (mean [SD] age, 63.2 [18.3] years; 45.2% women). The sensitivity (95% CI) for laboratory confirmed cases, i.e. repeatedly tested patients were as follows: 85.7% (81.5–89.1%) inpatients; 95.5% (92.2–97.5%) outpatients, 89.9% (88.2–92.1%) all. When also patients that were graded as high suspicion but never tested positive were included in the denominator, the following sensitivity values (95% CI) were observed: 67.5% (62.9–71.9%) inpatients; 34.9% (31.4–38.5%) outpatients; 47.3% (44.4–50.3%) all.Conclusions and relevanceThe clinical sensitivity of SARS-CoV-2 RT-PCR testing was only moderate at best. The relatively high false negative rates of SARS-CoV-2 RT-PCR testing need to be accounted for in clinical decision making, epidemiological interpretations and when using RT-PCR as a reference for other tests.Key PointsQuestionWhat is the clinical sensitivity of SARS-CoV-2 RT-PCR test?FindingsIn this population-based retrospective study on medical records of 1,814 outpatients and 1,194 inpatients, the clinical sensitivity of SARS-CoV-2 RT-PCR was 47.3–89.9%.MeaningThe false negative rates of SARS-CoV-2 RT-PCR testing need to be accounted for in clinical decision making, epidemiological interpretations and when using RT-PCR as a reference for other tests.

scholarly journals Droplet Digital PCR – A Superior Complementary Technique for SARS-CoV-2 Detection

2020 ◽  
pp. 12-15
Author(s):  
I. M. Hussaini ◽  
S. Gide ◽  
B. Musa ◽  
M. A. Sulaiman ◽  
A. Usman
Keyword(s):  
Sensitivity And Specificity ◽  
False Negative ◽  
Standard Technique ◽  
Digital Pcr ◽  
Droplet Digital Pcr ◽  
Reference Standard ◽  
Rt Pcr ◽  
Negative Results ◽  
False Negative Results ◽  
Current Reference Standard

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.

EVALUATION OF PERFORMANCE OF NINE SEROLOGICALASSAYS FOR THE DETECTION OF SARS-COV-2 ANTIBODIES.

2021 ◽  
pp. 60-62
Author(s):  
Tagajdid Mohamed Rida ◽  
Konzi Clémence ◽  
El Kochri Safae ◽  
Elannaz Hicham ◽  
Abi Rachid ◽  
...  
Keyword(s):  
Clinical Performance ◽  
Current Knowledge ◽  
False Negative ◽  
Antibody Test ◽  
Antibody Detection ◽  
Rt Pcr ◽  
Igg Antibody ◽  
Serological Tests ◽  
Blood Samples ◽  
Test Kit

Introduction: Currently, polymerase chain reaction (PCR) based viral RNAdetection is the standard for COVID-19 diagnosis [2]. Though, RNA testing based on throat or nasopharyngeal swabs has shown a number of false-negative results. Antibody detection tests have been developed to detect specic antibodies, IgM and IgG, to SRAS-CoV-2 virus. The clinical relevance of these tests is still under evaluation and is highly related to their clinical performance. Our objective is to assess analytical performances of nine SARS-CoV-2 antibodies immunoassays. Materiel and Method: We collected 80 blood samples from PCR-conrmed COVID-19 patients diagnosed in our Virology department (20 samples collected at day 10 after the onset of symptoms, 60 collected after day 14 following the onset of symptoms) and 20 blood samples from patients SARS-CoV-2 RT-PCR negative. All sera were tested with nine SARS-CoV-2 antibodies immunoassays ARCHITECT SARS-CoV-2 IgG® (Abbott), COVID-19 VIRCLIA® IgG MONOTEST (Vircell), COVID-19 VIRCLIA® IgM+IgA MONOTEST (Vircell), COVID-19 ELISA IgG® (Vircell), COVID-19 ELISA IgM+IgA® (Vircell), Elecsys® Anti-SARS-CoV-2 (Roche), FREND® COVID-19 IgG/IgM Duo (NanoEntek), COVID-PRESTO® (AAZ) and COVID-19 (SARS-CoV-2) IgM/IgG Antibody Test Kit® (Labnovation Technologies). Results: Sensitivity of tests increases once the seroconversion to anti-SARS-CoV-2 IgG positive in most individuals occurs toward the end of week 2 post-infection. COVID-19 PRESTO had the best accuracy in our study showing 100% sensitivity after day 14 following the onset of symptoms. All of the tests had a specicity of 100%. Conclusion: Serological tests are sensitive for the latest stages of COVID-19 infection. Recommendations on using SRAS-COV-2 antibody detection tests are continuously improving based on current knowledge of host antibody responses during infection. They are of great value in cases presenting COVID-19 symptoms with negative RT-PCR.

scholarly journals Real-world assessment of Fluorecare SARS-CoV-2 Spike Protein Test Kit

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Gian Luca Salvagno ◽  
Gianluca Gianfilippi ◽  
Laura Pighi ◽  
Simone De Nitto ◽  
Brandon M. Henry ◽  
...  
Keyword(s):  
Clinical Performance ◽  
Diagnostic Testing ◽  
Real Life ◽  
Spike Protein ◽  
Nasopharyngeal Swab ◽  
Molecular Testing ◽  
Diagnostic Efficiency ◽  
Predictive Values ◽  
Test Kit ◽  
Study Population

Abstract Objectives Since commercial SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) antigen rapid detection tests (Ag-RDTs) display broad diagnostic efficiency, this study aimed to evaluate the clinical performance of Fluorecare SARS-CoV-2 Spike Protein Test Kit in a real-life scenario. Methods The study population consisted of a series of patients undergoing SARS-Cov-2 diagnostic testing at Pederzoli Hospital of Peschiera del Garda (Verona, Italy). A nasopharyngeal swab was collected upon hospital admission and assayed with molecular (Altona Diagnostics RealStar® SARSCoV-2 RT-PCR Kit) and antigen (Fluorecare SARS-CoV-2 Spike Protein Test Kit) tests. Results The study population consisted of 354 patients (mean age, 47 ± 20 years; 195 women, 55.1%), 223 (65.8%) positive at molecular testing. A significant correlation was found between Fluorecare SARS-CoV-2 Spike Protein Test Kit and Altona (both S and E genes: r=−0.75; p<0.001). The cumulative area under the curve in all nasopharyngeal samples was 0.68. At ≥1.0 S/CO manufacturer’s cut-off, the sensitivity, specificity, negative and positive predictive values were 27.5, 99.2, 41.5 and 98.5%, respectively. Considerable improvement of sensitivity was observed as Ct values decreased, becoming 66.7% in samples with mean Ct values <30, 90.5% in those with mean Ct values <25, up to 100% in those with mean Ct values <20. Conclusions The modest sensitivity and negative predictive value of Fluorecare SARS-CoV-2 Spike Protein Test Kit makes unadvisable to use this assay as surrogate of molecular testing for definitively diagnosing SARS-CoV-2 infection, though its suitable sensitivity at high viral load could make it a reliable screening test for patients with higher infective potential.

scholarly journals Reconstructed diagnostic sensitivity and specificity of the RT-PCR test for COVID-19

2020 ◽  
Author(s):  
Nikhil S. Padhye
Keyword(s):  
Sensitivity And Specificity ◽  
Prior Probability ◽  
False Negative ◽  
Diagnostic Sensitivity ◽  
Rt Pcr ◽  
Predictive Values ◽  
Probabilistic Knowledge ◽  
Diagnostic Sensitivity And Specificity ◽  
Pcr Targeting ◽  
Pcr Test

AbstractBackgroundReal-time reverse transcription polymerase chain reaction (RT-PCR) targeting select genes of the SARS-CoV-2 RNA has been the main diagnostic tool in the global response to the COVID-19 pandemic. However, the diagnostic accuracy of the test has not been studied systematically outside of the laboratory setting. The aim of this study is to provide estimates of the diagnostic sensitivity and specificity of the RT-PCR test developed by China CDC.MethodsThe study design is a secondary analysis of published findings on 1014 patients in Wuhan, China, of whom 601 tested positive and 413 were negative for COVID-19. Sensitivity and specificity were reconstructed using a Bayesian approach from probabilistic knowledge of the diagnostic errors. Predictive values of the test were calculated, resulting in estimates for the number of confirmatory tests that are needed for establishing the presence or absence of COVID-19, depending on the prior probability of a patient having the disease.ResultsThe sensitivity of the RT-PCR diagnostic test was estimated to be 0.777 (95% CI: 0.715, 0.849), while the specificity was 0.988 (95% CI: 0.933, 1.000). The confidence intervals include sampling error in addition to the error due to probabilistic knowledge of the data.DiscussionThe Chinese version of the RT-PCR test had a conspicuous rate of false negative results, likely missing between 15% and 29% of patients with COVID-19. For a patient with a prior probability of COVID-19 greater than 18%, at least two negative test results would be needed to lower the chances of COVID-19 below 5%. Caution is advised in generalizing these findings to other versions of the RT-PCR test that are being used in diverse geographic regions.

scholarly journals Evaluation of Performance of Detection of IgG and IgM Antibody Against Spike Protein of SARS-CoV-2 by a Rapid Kit in a Real-Life Hospital Setting

2021 ◽  
Author(s):  
Monica Irungbam ◽  
Anubhuti Chitkara ◽  
Vijay Kumar Singh ◽  
Subash Chandra Sonkar ◽  
Abhisekh Dubey ◽  
...  
Keyword(s):  
Real Life ◽  
Hospital Setting ◽  
Antibody Test ◽  
Protein S ◽  
Spike Protein ◽  
Diagnostic Efficiency ◽  
Rt Pcr ◽  
Antibody Testing ◽  
Diagnostic Efficacy ◽  
Rapid Antibody

Abstract Background Antibody testing are often used for serosurveillance of COVID-19. ELISA and Chemiluminesence based antibody test are quiet sensitive and specific for such serological testing. Rapid antibody tests are developed and effectively used for this purpose. But their diagnostic efficiency needs to be evaluated. So, the present study was conducted in a dedicated COVID-19 hospital in Delhi, India to evaluate the diagnostic efficacy of a Rapid antibody kit for COVID-19. Material and Method : Sixty COVID-19 confirmed cases by RT-PCR were recruited and categorized as early, intermediate and late cases based on the number of days of their first RT-PCR + ve tests, 20 subjects in each category. Twenty samples from pre-covid era were taken as controls. IgM and IgG antibodies against RBD of spike protein (S) of SARS-CoV2 virus were detected by Rapid antibody test and compared with total antibody against the nucleocapsid (N) antigen of SARS-CoV-2 by Electrochemiluminescence based Immunoassay (ECLIA). Results The detection IgM against Receptor binding domain (RBD) of spike protein by rapid kit was 0-37.5% sensitive and 0-100% specific for diagnosis of SARS-CoV-2 infection. However, efficacy of detection of IgG by rapid kit was 87–89% sensitive and 75–100% specific when compared with total antibody against N antigen measured by ECLIA based immunoassay. Conclusion It can be concluded that detection of IgM against RBD of S protein by rapid kit is not effective but IgG detection can be used as an effective diagnostic tool for SARS-COV-2 infection.

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 Viral Dynamics and Real-Time RT-PCR Ct Values Correlation with Disease Severity in COVID-19

Diagnostics ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1091
Author(s):  
Ali A. Rabaan ◽  
Raghavendra Tirupathi ◽  
Anupam A Sule ◽  
Jehad Aldali ◽  
Abbas Al Mutair ◽  
...  
Keyword(s):  
Viral Load ◽  
Real Time ◽  
Disease Severity ◽  
False Negative ◽  
Influential Factors ◽  
Confirmatory Test ◽  
Acid Extraction ◽  
Rt Pcr ◽  
Viral Kinetics ◽  
Ct Value

Real-time RT-PCR is considered the gold standard confirmatory test for coronavirus disease 2019 (COVID-19). However, many scientists disagree, and it is essential to understand that several factors and variables can cause a false-negative test. In this context, cycle threshold (Ct) values are being utilized to diagnose or predict SARS-CoV-2 infection. This practice has a significant clinical utility as Ct values can be correlated with the viral load. In addition, Ct values have a strong correlation with multiple haematological and biochemical markers. However, it is essential to consider that Ct values might be affected by pre-analytic, analytic, and post-analytical variables such as collection technique, specimen type, sampling time, viral kinetics, transport and storage conditions, nucleic acid extraction, viral RNA load, primer designing, real-time PCR efficiency, and Ct value determination method. Therefore, understanding the interpretation of Ct values and other influential factors could play a crucial role in interpreting viral load and disease severity. In several clinical studies consisting of small or large sample sizes, several discrepancies exist regarding a significant positive correlation between the Ct value and disease severity in COVID-19. In this context, a revised review of the literature has been conducted to fill the knowledge gaps regarding the correlations between Ct values and severity/fatality rates of patients with COVID-19. Various databases such as PubMed, Science Direct, Medline, Scopus, and Google Scholar were searched up to April 2021 by using keywords including “RT-PCR or viral load”, “SARS-CoV-2 and RT-PCR”, “Ct value and viral load”, “Ct value or COVID-19”. Research articles were extracted and selected independently by the authors and included in the present review based on their relevance to the study. The current narrative review explores the correlation of Ct values with mortality, disease progression, severity, and infectivity. We also discuss the factors that can affect these values, such as collection technique, type of swab, sampling method, etc.

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