scholarly journals The performance of the SARS-CoV-2 RT-PCR test as a tool for detecting SARS-CoV-2 infection in the population. A survey of routine laboratory RT-PCR test results from the region of Muenster, Germany

Author(s):  
Andreas Stang ◽  
Johannes Robers ◽  
Birte Schonert ◽  
Karl-Heinz Joeckel ◽  
Angela Spelsberg ◽  
...  

Objectives: To evaluate the population-based performance of the SARS-CoV-2 RT-PCR test as a tool for detecting SARS-CoV-2 infection during the pandemic in 2020. Methods: We analysed SARS-CoV-2 RT-PCR results of 162,457 people living in Muenster, Germany screened at nursing homes, testing sites, at schools, regional hospitals, and by general practitioners. All PCRs were done with the same cobas SARS-CoV-2 RT-PCR system (Roche Diagnostics). We stratified positive RT-PCR results by cycle threshold (Ct) values, periods of the national test strategy, age, sex, and symptoms. Results: Among 162,457 individuals, 4164 (2.6%) had a positive RT-PCR test result, defined as Ct<40. Depending on the national test strategy, higher positive rates were associated with testing predominantly symptomatic people. Children (0-9 years) and older adults (70+ years). Only 40.6% of test positives showed low Ct values < 25 (potentially infectious). The percentage of Ct values below 25 was lower among children (0-9), adolescents (10-19), and among the elderly (70+ years). Conclusions: RT-PCR testing as a tool for mass screening should not be used alone as a base for pandemic decision making including measures such as quarantine, isolation, and lockdown.

2021 ◽  
pp. 003022282110598
Author(s):  
Hümeyra Aslaner ◽  
Betül Özen ◽  
Zeliha K. Erten ◽  
Mebrure Beyza Gökçek

Urgent measures were taken for those at the age of 65 and over who were at the risk group all over the world due to the COVID-19 pandemic. It is known that many individuals at the age of 65 and over have experienced anxiety due to the uncertainties. This study aimed to determine the anxiety and death anxiety in individuals aged 65 and over who were isolation at home due to being diagnosed with COVID-19 or being in contact during the pandemic process. The study is descriptive and cross-sectional. It was performed with 656 home-quarantined individuals aged between 65–80 years with positive or negative real-time polymerase chain reaction (RT-PCR) test result. A form including questions about the death anxiety and the Coronavirus Anxiety Scale Short Form prepared by the researchers were administered to the individuals by phone call. Of the participants, 49.5% were male. Median COVID-19 anxiety score was 4 (0–18). Anxiety scores of the male and female participants were similar. Participants with negative polymerase chain reaction (PCR) results and those with death anxiety had higher COVID anxiety scores. Death anxiety has increased by 1.661 times in male gender, 1.983 times in RT-PCR positivity and 0.146 times in the presence of symptoms. Individuals with positive COVID-19 test results or those aged 65 and over who had death anxiety and negative COVID-19 test result but who were in home-isolation due to being a contact had higher anxiety score. For this reason, those with death anxiety can be supported in line with their religious beliefs to reduce anxiety. Those with negative PCR test results in quarantine can be adequately informed about the COVID-19.


2020 ◽  
Vol 222 (11) ◽  
pp. 1784-1788 ◽  
Author(s):  
You Zou ◽  
Bin-Ru Wang ◽  
Liu Sun ◽  
Shan Xu ◽  
Yong-Gang Kong ◽  
...  

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.


2021 ◽  
Vol 15 (9) ◽  
pp. 2474-2476
Author(s):  
Maham Munir Awan ◽  
Afshan Noreen ◽  
Farah Kalsoom ◽  
Muhammad Tahir ◽  
Umaima Majeed ◽  
...  

Objective: To determine the accuracy of CT chest in diagnosis of COVID-19 taking RT-PCR-testing as gold standard. Materials and Methods: A total of 150 patients of suspicion of COVID-19 who were referred for CT Chest in Radiology Department of Nishtar Medical University Multan from June-2020 to May-2021 were included. In all patients, two RT-PCR test results were obtained with 7 days of admission in hospital. Presence of any of these positive was labelled as COVID-19 infection. CT chest was performed in all patients within 2 days of admission in hospital using 128 slices CT scan machine. The diagnosis of COVID-19 infection was made according to the recommendations by Radiological Society of North America (RSNA) protocol. Results: Mean age was 51.3±14.7 years. 78 (52%) patients were male and 72 (48%) patients were female. RTPCR test was positive in 89 (59.3%) patients. While the CT chest findings were suggestive of COVID-19 infection in 130 (86.7%) patients. The sensitivity of CT chest was 95.5%, specificity 26.2%, PPV wad 65.4% and NPV was 80.0%. Conclusion: CT chest has a very good sensitivity for detection of COVID-19, it can be used as a rapid diagnostic tool especially in areas of pandemic. However, the specificity of CT chest is low, that can limit its use in low COVID-19 affected areas. Keywords: COVID-19, Computed tomography, False Positive, True Positive, Positive Predictive Value, Negative Predictive Value.


2021 ◽  
pp. 51-52
Author(s):  
Tharani Putta ◽  
Kaushik Deconda

BACKGROUND AND OBJECTIVE: Role of chest CT in diagnosis of corona virus disease 2019 (COVID-19) has been controversial. The purpose of this study is to evaluate the diagnostic performance of chest CT when utilizing COVID-19 Reporting and Data System (CO-RADS). METHODOLOGY: Retrospective study including consecutive patients with positive SARS-CoV-2 RT-PCR test (initial or repeat test) and chest CT done in our institute between June and September 2020. Spectrum of CT ndings, CO-RADS score and 25 point CT severity score (CTSS) were recorded. RESULTS: A total of 300 consecutive patients with SARS-CoV-2 infection were included in the analysis. Out of the 168 patients who underwent CT prior to positive RT-PCR result, 125 (74.4%) had CO-RADS 3, 4 or 5 score on chest CT. 32 study patients (10.6%) had initial negative RT-PCR of which 24 (75%) had CO-RADS 4 or 5 score. Of the total patients with CO-RADS 3 to 5 score (227), 20 (8.8%) had severe lung involvement (CTSS 18-25), 83 (36.6%) had moderate lung involvement (CTSS 8-17) and 124 (54.6%) had mild lung involvement (CTSS 1-7). The mean CTSS was 7.9 with mean lobar score being higher in lower lobes (RLL=1.82, LLL=1.78) compared to the upper and middle lobes (RUL=1.61, RML=1.19, LUL=1.53). CONCLUSION:CT using CO-RADS scoring system has good diagnostic performance. In addition to assessing disease severity, it plays a vital role in triage of patients with suspected COVID-19 especially when there is limited availability of SARS-CoV-2 RT-PCR tests, delay in RT-PCR test results or in negative RT-PCR cases when there is high index of clinical suspicion.


Epidemiologia ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 540-552
Author(s):  
Peter Kamp Busk ◽  
Thomas Birk Kristiansen ◽  
Allan Engsig-Karup

During the COVID-19 pandemic, Denmark has pursued a mass testing strategy culminating in the testing of 12.167 individuals per 100,000 inhabitants per day during the spring of 2021. The strategy included free access to COVID-19 testing, and since 2021, compulsory documentation for negative tests or vaccination has been required for access to workplace, educational institutions, restaurants, and many other places. Testing and subsequent isolation if testing was positive were voluntary. The present study provides an analysis of whether testing frequency in Denmark showed any correlation to hospitalizations throughout the relevant stages of the pandemic. Mass testing was found not to correlate significantly with the number of hospitalizations during the pandemic. Interestingly, during the highest level of testing in spring 2021 the fraction of positive tests increased slightly; thus, the Danish mass testing strategy, at its best, failed to reduce the prevalence of COVID-19. Furthermore, the relationship between positives in antigen testing and in rt-PCR testing indicated that many patients were not tested early in their infection when the risk of transmission was at the highest. In conclusion, the Danish mass testing strategy for COVID-19 does not appear to have a detectable correlation to the number of hospitalizations due to COVID-19.


2020 ◽  
Vol 9 (11) ◽  
pp. 3552 ◽  
Author(s):  
Yolanda Cuñarro-López ◽  
Óscar Cano-Valderrama ◽  
Pilar Pintado-Recarte ◽  
Ignacio Cueto-Hernández ◽  
Blanca González-Garzón ◽  
...  

This study was designed to examine maternal-perinatal outcomes in pregnant women with suspected coronavirus disease 2019 (COVID-19) according to the result of a real-time reverse transcription polymerase chain reaction (RT-PCR) test and to investigate possible variables that could be useful for predicting a negative RT-PCR result. Participants of this retrospective cohort study were obstetrics patients with suspected COVID-19 who underwent an RT-PCR test in a tertiary hospital in Madrid, Spain. Maternal-perinatal features were analysed according to the results of this test. Clinical, radiological and analytical characteristics that could be associated with a negative result were also explored. In a final subgroup analysis, patients were included if they had pneumonia and a negative test result for the virus. Out of the 111 obstetric patients with suspected COVID-19 that were enrolled, 38.7% returned a negative result. In this RT-PCR-negative group, we recorded lower rates of pneumonia (21.4% vs. 45.6%, p = 0.009), severe or critical clinical features (4.7% vs. 11.8% and 0.0% vs. 5.9%, p = 0.02, respectively), lower lactate dehydrogenase (LDH) levels (168 UI/L vs. 224.5 UI/L, p = 0.003), a greater need for maternal treatment (60.3% vs 24.4%, p < 0.001), a reduced need for oxygen therapy (2.4% vs 28.8%, p < 0.001) and a lower rate of intensive care unit admission (0.0% vs. 3.7%, p = 0.046) than the RT-PCR-positive group. While no differences were found in other variables, the monocyte count was higher (946.2/μL vs. 518.8/μL, p = 0.022) in this group. The predictive model for a negative test result included the monocyte count, LDH level and no need for oxygen therapy. This model was able to identify 73.5% of patients with a negative RT-PCR result. Only 11% of the patients with pneumonia testing negative for the virus had IgG antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The proportion of pregnant women with suspected COVID-19 and a negative RT-PCR result was nearly 39%. In these patients, the symptoms were mild and the systemic severity of the disease was lower. The monocyte count, LDH level and no need for oxygen therapy were the factors that were more related to a negative test result in this group. These variables could be used to guide the management of patients with suspected COVID-19, mainly while waiting for RT-PCR results or in settings where this test is not available.


2021 ◽  
Vol 8 ◽  
Author(s):  
Yousef A. Fouad ◽  
Tougan Taha Abdelaziz ◽  
Anas Askoura ◽  
Mohamed Ibrahim Saleh ◽  
Mohammad S. Mahmoud ◽  
...  

Objective: To determine if there was an increase in the rate of cases presenting with rhino-orbital-cerebral mucormycosis (ROCM) to a tertiary care center during the first wave of the coronavirus disease 2019 (COVID-19) pandemic and the characteristics of the presenting cases.Methods: Retrospective observational study reviewing ROCM cases presenting from March 25 until September 25, 2020. Cases fulfilling the clinical, radiological, and pathological/microbiological criteria for diagnosis with ROCM were included. The number of cases presenting during the designated interval, their COVID-19 status, comorbidities, and clinical presentation were analyzed. The number of cases during the corresponding interval in the previous 3 years was used as reference to detect if there was a recent spike.Results: Of the 12 ROCM cases identified, 5 had a concurrent positive reverse transcription PCR (RT-PCR) test result for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), 1 had a prior positive result, and 6 did not have concurrent nor prior positive test results. Nine of the 12 cases had poorly controlled diabetes mellitus, and 2 cases had a hematological malignancy. All cases had orbital invasion, and eight cases had cerebral invasion. The number of cases identified during the interval is much higher than the numbers presenting in the prior 3 years during equivalent intervals (range, one to two cases) than those reported in the literature in different settings in the pre-pandemic era.Conclusions: There is an increased rate of ROCM cases presenting to our center during the first wave of the COVID-19 pandemic. This is a preliminary report, and further studies are needed to corroborate the findings and explain possible underlying links.


Author(s):  
Bushra A. A. Albazi ◽  
Dr Noof. Albaz ◽  
Dr Nayef. Alqahtani ◽  
Dr. Angham Salih ◽  
Dr Rafat Mohtasab

A large number of patients with coronavirus disease 2019 (COVID-19) present at hospitals. There are a limited number of isolation rooms open, and patients must often wait a long time to get a reverse transcription-polymerase chain reaction (RT-PCR) test done. This necessitates the introduction of effective triage plans. A patient with suspicions is referred to an emergency room (ED) depending on their medical record for a simple physical assessment, blood test findings, and chest imaging.A retrospective study design was conduct at Prince Sultan Medical Military City (PSMMC). Ethical approval was obtained from the institutional board to wave the consent forms since it is a retrospective study. Only the primary investigator has had the data access to the patients’ medical records. The collected patient records were under specific categories, including symptoms score starts from 5 and above, RT-PCR test result done after CXRP imaging, the patient admitted to the emergency department (ED). Excluding all CXRP done after RT-PCR TEST, positive Covid 19 admitted to the intensive care unit (ICU), pediatric patients, and patients with score symptoms were less than five. Two experienced radiologists reviewed the images blindly, and the inter-observer reliability of observations noted by the radiologists was calculated. As for the relationship between the x-ray reading and the RT-PCR test result, our results showed a high correlation between the variables (chi-square χ² = 12.44, with df =1, and p<0.001). The sensitivity of x-ray diagnosing covid19 was 65.52 %, while the specificity was 54.51 %, and the accuracy of radiologists reading was 58.17 %. Furthermore, the positive predictive value (PPV) was 41.76 %, and the negative predictive value (NPV) was 76.05%. Finally, the false positive rate (type-i error (alpha) was 45.49%, and the false-negative rate (type-ii error (beta) was 34.48% Our research findings show that CXRP imaging can detect COVID-19 infection in symptomatic patients and can be a valuable addition to RT-PCR testing. In an inpatient ED environment where availability of test kits, laboratory equipment, and laboratory personnel is compromised and risks delaying patient treatment and hospital workflow, serial CXRP could theoretically be used as an adjunct diagnostic function and monitoring in patients suspected of having COVID-19.


2021 ◽  
Author(s):  
Juri Smirnov ◽  
Thomas Fenner

In this work, we put forward a novel test strategy, that allows to significantly increase the test capacity for SARS-CoV-2. The test strategy is based on an a priory risk assessment scheme, that allows to dynamically find and adapt an optimal clustering size of test pools. We, furthermore, suggest a method to overcome the efficiency loss of test clustering by avoiding concentration losses in the test samples. We validated our method with several thousand probe pools performing RT-PCR tests, and found it highly effective.


Author(s):  
Muhammet Asena ◽  
ilyas yolbaş ◽  
murat Kanğın

Background: The pandemic of the new coronavirus disease (COVID-19) continues to be a major health problem globally. In this study, clinical findings, radiological findings, laboratory findings and polymerase chain reaction (PCR) test results were evaluated according to age groups in pediatric patients with COVID-19. Methods: In this study, PCR (+) and PCR (-) 278 cases diagnosed with COVID-19 between March 15, 2020 and September 30, 2020 were assessed considering clinical symptoms, radiological and laboratory findings and RT-PCR test results. Results: 43.9% of the cases consisted of RT-PCR (+) and 56.1% of RT-PCR (-) cases. Fever was observed at the rate of 64.7%, cough 53.2%, respiratory distress 12.2%, myalgia 24.5%, diarrhea 12.9%, chest X-ray findings 48.2% and computed tomography findings 43.6%. Diarrhea and cough, alanine aminotransferase, aspartate aminotransferase, leukocyte and lymphocyte elevation were determined as significantly higher in younger age group cases, while high myalgia and neutrophilia was observed in older age group children (p <0.05). Fever, high CRP, leukocytosis frequency, high neutrophil, were significantly higher in PCR(-) cases and the frequency of respiratory distress, high lymphocyte and chest computed tomography findings in PCR(+) cases (p <0.05). Conclusion: COVID-19 infection may indicate different nonspecific clinical, laboratory and radiological findings in children according to both adults and pediatric age groups. In addition, the results of the PCR test may give erroneous results in cases due to conditions such as fever, respiratory distress, high CRP, leukocytosis, high neutrophil and CT finding. Keywords: pediatric, COVID-19, RT-PCR


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