Evaluation of RT-LAMP Assay for Rapid Detection of SARS-CoV-2.

OBJECTIVE: To evaluate the accuracy of the reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay for rapid detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in community or primary-care settings. METHOD: We systematically searched the Web of Science, Embase, PubMed, and Cochrane Library databases. We conducted quality evaluation using ReviewManager software (version 5.0). We then used MetaDisc software (version 1.4) and Stata software (version 12.0) to build forest plots, along with a Deeks funnel plot and a bivariate boxplot for analysis. RESULT: Overall, the sensitivity, specificity, and diagnostic odds ratio were 0.79, 0.97, and 328.18, respectively. The sensitivity for the subgroup with RNA extraction appeared to be higher, at 0.88 (0.86-0.90), compared to the subgroup without RNA extraction, at 0.50 (0.45-0.55), with no significant difference in specificity. CONCLUSION: RT-LAMP assay exhibited high specificity regarding current SARS-CoV-2 infection. However, its overall sensitivity was relatively moderate. Extracting RNA was found to be beneficial in improving sensitivity.

Diagnostic performance of chest CT findings of COVID-19 with RT-PCR negative.

COVID-19 presented with lung abnormalities on computed tomography (CT) scans in patient with false negative RT-PCR, which are helpful in diagnosis of this emerging global health emergency. It's a case report the young woman of 35-year-old patient with 2019-nCoV pneumonia confirmed with IgM-IgG serology underwent thin-section Chest CT. Our patient has the Chest CT with some lung abnormalities, the Ground-glass opacities, crazy paving pattern and smooth interlobular septal thickening. The clinical findings and with conspicuous ground grass opacity lesions in the peripheral and posterior lungs on CT are highly suspected of 2019-nCoV pneumonia.

Implementation of a Deep Learning-Based Computer-Aided Detection System for the Interpretation of Chest Radiographs in Patients Suspected for COVID-19.

OBJECTIVE: To describe the experience of implementing a deep learning-based computer-aided detection (CAD) system for the interpretation of chest X-ray radiographs (CXR) of suspected coronavirus disease (COVID-19) patients and investigate the diagnostic performance of CXR interpretation with CAD assistance. MATERIALS AND METHODS: In this single-center retrospective study, initial CXR of patients with suspected or confirmed COVID-19 were investigated. A commercialized deep learning-based CAD system that can identify various abnormalities on CXR was implemented for the interpretation of CXR in daily practice. The diagnostic performance of radiologists with CAD assistance were evaluated based on two different reference standards: 1) real-time reverse transcriptase-polymerase chain reaction (rRT-PCR) results for COVID-19 and 2) pulmonary abnormality suggesting pneumonia on chest CT. The turnaround times (TATs) of radiology reports for CXR and rRT-PCR results were also evaluated. RESULTS: Among 332 patients (male:female, 173:159; mean age, 57 years) with available rRT-PCR results, 16 patients (4.8%) were diagnosed with COVID-19. Using CXR, radiologists with CAD assistance identified rRT-PCR positive COVID-19 patients with sensitivity and specificity of 68.8% and 66.7%, respectively. Among 119 patients (male:female, 75:44; mean age, 69 years) with available chest CTs, radiologists assisted by CAD reported pneumonia on CXR with a sensitivity of 81.5% and a specificity of 72.3%. The TATs of CXR reports were significantly shorter than those of rRT-PCR results (median 51 vs. 507 minutes; p < 0.001). CONCLUSION: Radiologists with CAD assistance could identify patients with rRT-PCR-positive COVID-19 or pneumonia on CXR with a reasonably acceptable performance. In patients suspected with COVID-19, CXR had much faster TATs than rRT-PCRs.

Diagnostic yield of serial SARS-CoV-2 testing in hospitalized patients.

BACKGROUND: The detection rate of SARS-CoV-2 by polymerase chain reaction (PCR) varies depending on the time since exposure and is highest around the time of symptom onset. It is conceivable that patients who are incubating SARS-CoV-2 may screen negative at admission and develop transmissible but undetected asymptomatic or pre-symptomatic disease while in hospital. The incidence of COVID-19 in Montreal, Canada started to increase in December 2020. In anticipation of a much larger rise after the holiday period, the McGill University Health Centre implemented serial SARS-CoV-2 testing for all admitted patients on day 5 and 10 after admission, to evaluate the clinical utility of serial SARS-CoV-2 testing among patients who test negative on admission screening. METHODS: We retrospectively analyzed the diagnostic yield of SARS-CoV-2 serial testing for patients admitted between January 4, 2021 and April 30, 2021. RESULTS: A total of 1,505 patients underwent serial testing at day 5 and 841 patients underwent serial testing at day 10. Only 10 patients were positive on serial testing at day 5 and only 12 patients were positive on serial testing at day 10, for a yield at day 5 and day 10 of 0.7% and 1.4%, respectively. CONCLUSIONS: The yield of serial SARS-CoV-2 testing was 0.7% at day 5 and 1.4% at day 10. We found that the yield of serial testing was higher when the community incidence was higher and could be considered in this situation. Policies which target repeat testing towards symptomatic or exposed individuals appear to be effective in identifying those with a positive test while admitted but testing negative upon admission.

HISTORIQUE: Le taux de détection du SRAS-CoV-2 par l'amplification en chaîne par polymérase (PCR) varie en fonction de la période écoulée depuis l'exposition et est plus élevé aux alentours du moment d'apparition des symptômes. Il se peut que les patients en période d'incubation du SRAS-CoV-2 obtiennent un résultat négatif à leur admission, puis développent une maladie asymptomatique ou présymptomatique non détectée pendant leur séjour hospitalier. L'incidence de COVID-19 a commencé à augmenter à Montréal, au Canada, en décembre 2020. En prévision d'une hausse beaucoup plus marquée après la période des fêtes, le Centre universitaire de santé McGill a mis en œuvre des tests sériels du SRAS-CoV-2 pour tous les patients hospitalisés le cinquième et le dixième jour après leur hospitalisation, afin d'évaluer l'utilité clinique des tests sériels du SRAS-CoV-2 chez les patients qui avaient reçu un résultat négatif lors du dépistage à leur admission. MÉTHODOLOGIE: Les chercheurs ont procédé à une analyse rétrospective du taux diagnostique des tests sériels du SRAS-CoV-2 chez les patients hospitalisés entre le 4 janvier et le 30 avril 2021. RÉSULTATS: Au total, 1 505 patients se sont soumis au test sériel le cinquième jour et 841 patients, le dixième jour. Seulement dix patients ont obtenu un résultat positif au test sériel le cinquième jour (0,7 %) et seulement 12, le dixième jour (1,4 %). CONCLUSIONS: Le taux de résultats positifs aux tests sériels du SRAS-CoV-2 s'élevait à 0,7 % le cinquième jour et à 1,4 % le dixième jour. Il était plus marqué lorsque l'incidence communautaire était plus élevée; les tests sériels pourraient être envisagés dans cette situation. Les politiques qui ciblent les tests répétés chez les personnes symptomatiques ou exposées semblent efficaces pour détecter celles dont le résultat est positif pendant leur hospitalisation, mais qui ont obtenu un résultat négatif à leur admission.

Diagnostic accuracy of SARS-CoV-2 saliva antigen testing in a real-life clinical setting.

BACKGROUND: SARS-CoV-2 antigen tests with saliva facilitate examination in settings that lack trained personnel. However, little is known about the diagnostic accuracy in real-life clinical settings. Therefore, we studied the diagnostic accuracy of a saliva antigen test in diagnosing SARS-CoV-2 infection in a primary/secondary care testing facility. METHODS: Individuals who presented at a COVID-19 testing facility affiliated with a Swiss university hospital were prospectively recruited (n=377). Saliva specimen was obtained, and the PCL Inc. COVID19 Gold antigen test was conducted in parallel with 2 real-time polymerase chain reaction (RT-PCR) assays from a nasopharyngeal swab. RESULTS: RT-PCR results were positive in 53 individuals, corresponding to a prevalence of 14.1% (missing material in 1 individual). The PCL saliva antigen test was positive in 22 individuals (5.8%) and negative in 354 (93.9%). The sensitivity of the saliva antigen test was 30.2% (95% confidence interval 18.3, 44.3), both overall and in symptomatic individuals. The specificity was 98.1% (96.0, 99.3). CONCLUSIONS: The diagnostic accuracy of a SARS-CoV-2 saliva antigen test in a primary/secondary care testing facility was remarkably lower than that reported in the manufacturer's specifications.

Diagnostic value of chest CT scanning for determination of Covid-19 severity in individual lung lobes.

INTRODUCTION AND OBJECTIVE: CT examination is an important diagnostic tool in assessment of the severity of the infection and course of the disease. The aim of the study was to evaluate the degree and frequency of involvement of individual lung lobes and the population Lobe Involvement Coefficient (pLIC) value in the investigated population. MATERIAL AND METHODS: The analyzed material comprised 124 patients aged 18-92 years. CT examinations were performed using a 16- and 32-row CT LightSpeed apparatus. The spatial distribution of typical Covid -19 pathological changes was analyzed, divided into five lung lobes. The degree of the severity of lobe involvement was assessed using counters and percentages, as well as the population Lobe Involvement Coefficient (pLIC). Statistical analysis of data was performed with the use of Statistica 10.0 software. Values were measured on an oridinal scale. Anova Friedman's test was used to compare lobes. RESULTS: Statistically significant differences in the involvement between most of the individual lobes were shown. There was no statistically significant difference in the degree of lobe involvement between the left and right upper lobes, nor in the left and right lower lobes. The highest pILC was demonstrated for the lower lobe and the lowest value was obtained for the middle lobe. CONCLUSIONS: The lower lobes were affected most frequently and most severely, with no statistical difference between the right and left sides. The middle lobe was affected relatively least frequently and lightly. The introduced pLIC index allows quantitative assessment of individual lobes involvement in relation to the entire studied population.

Barriers to Community Pharmacists Referring Patients With Suspected COVID-19 Symptoms.

BACKGROUND: With the necessary skills available to community pharmacists, they are well equipped to relieve pressure on hospitals and general practices by providing referral services for symptomatic patients for COVID-19 testing. OBJECTIVE: The assessment of potential barriers that limit the successful implementation of a community pharmacy referral service for patients with suspected COVID-19 symptoms. METHODS: A questionnaire comprising of 100 questions was administered to one pharmacist by interview in 1023 working community pharmacies in 4 regions of Egypt between May 17 and May 30th 2020. RESULTS: Forty-five barriers were identified. Respondents (79%, n = 803) had difficulty obtaining an accurate patient history. Patient data confidentiality was a significant issue for pharmacists who had not received referral training, with these respondents being significantly (P = .010) less able to differentiate between COVID-19 and similar conditions. Respondents (68.8%, n = 698) were not confident in determining whether COVID-19 was the cause of the patient's presenting symptoms. A large majority (73.7%, n = 747) of respondents were worried about referring misdiagnosed patients and were concerned about the negative implications of proceeding with such a referral, including legal consequences. Of Respondents (71.7%, n = 727) reported that online referral was not easy, and 71.6% (n = 722) were unable to locate paper referral forms. Only a small number of pharmacists (11%, n = 112) preferred to report a referral in their own name. CONCLUSIONS: This study has demonstrated the potential of the community pharmacist's role as a point of referral for COVID-19 testing, and identified some major barriers to implementation of this. The lack of pharmacists' education, legal support, availability of referral forms, clarity of responsibility and unsupportive management teams are key obstacles that must be overcome for the successful implementation of a COVID-19 referral service.

Pre-endoscopy SARS-CoV-2 testing strategy during COVID-19 pandemic: the care must go on.

BACKGROUND: In response to the COVID-19 pandemic, endoscopic societies initially recommended reduction of endoscopic procedures. In particular non-urgent endoscopies should be postponed. However, this might lead to unnecessary delay in diagnosing gastrointestinal conditions. METHODS: Retrospectively we analysed the gastrointestinal endoscopies performed at the Central Endoscopy Unit of Saarland University Medical Center during seven weeks from 23 March to 10 May 2020 and present our real-world single-centre experience with an individualized rtPCR-based pre-endoscopy SARS-CoV-2 testing strategy. We also present our experience with this strategy in 2021. RESULTS: Altogether 359 gastrointestinal endoscopies were performed in the initial period. The testing strategy enabled us to conservatively handle endoscopy programme reduction (44% reduction as compared 2019) during the first wave of the COVID-19 pandemic. The results of COVID-19 rtPCR from nasopharyngeal swabs were available in 89% of patients prior to endoscopies. Apart from six patients with known COVID-19, all other tested patients were negative. The frequencies of endoscopic therapies and clinically significant findings did not differ between patients with or without SARS-CoV-2 tests. In 2021 we were able to unrestrictedly perform all requested endoscopic procedures (> 5000 procedures) by applying the rtPCR-based pre-endoscopy SARS-CoV-2 testing strategy, regardless of next waves of COVID-19. Only two out-patients (1893 out-patient procedures) were tested positive in the year 2021. CONCLUSION: A structured pre-endoscopy SARS-CoV-2 testing strategy is feasible in the clinical routine of an endoscopy unit. rtPCR-based pre-endoscopy SARS-CoV-2 testing safely allowed unrestricted continuation of endoscopic procedures even in the presence of high incidence rates of COVID-19. Given the low frequency of positive tests, the absolute effect of pre-endoscopy testing on viral transmission may be low when FFP-2 masks are regularly used.

Serological testing for SARS-CoV-2 antibodies in clinical practice: A comparative diagnostic accuracy study.

BACKGROUND: Serological tests are a powerful tool in the monitoring of infectious diseases and the detection of host immunity. However, manufacturers often provide diagnostic accuracy data generated through biased studies, and the performance in clinical practice is essentially unclear. OBJECTIVES: We aimed to determine the diagnostic accuracy of various serological testing strategies for (a) identification of patients with previous coronavirus disease-2019 (COVID-19) and (b) prediction of neutralizing antibodies against SARS-CoV-2 in real-life clinical settings. METHODS: We prospectively included 2573 consecutive health-care workers and 1085 inpatients with suspected or possible previous COVID-19 at a Swiss University Hospital. Various serological immunoassays based on different analytical techniques (enzyme-linked immunosorbent assays, ELISA; chemiluminescence immunoassay, CLIA; electrochemiluminescence immunoassay, ECLIA; and lateral flow immunoassay, LFI), epitopes of SARS-CoV-2 (nucleocapsid, N; receptor-binding domain, RBD; extended RBD, RBD+; S1 or S2 domain of the spike [S] protein, S1/S2), and antibody subtypes (IgG, pan-Ig) were conducted. A positive real-time PCR test from a nasopharyngeal swab was defined as previous COVID-19. Neutralization assays with live SARS-CoV-2 were performed in a subgroup of patients to assess neutralization activity (n = 201). RESULTS: The sensitivity to detect patients with previous COVID-19 was ≥85% in anti-N ECLIA (86.8%) and anti-S1 ELISA (86.2%). Sensitivity was 84.7% in anti-S1/S2 CLIA, 84.0% in anti-RBD+LFI, 81.0% in anti-N CLIA, 79.2% in anti-RBD ELISA, and 65.6% in anti-N ELISA. The specificity was 98.4% in anti-N ECLIA, 98.3% in anti-N CLIA, 98.2% in anti-S1 ELISA, 97.7% in anti-N ELISA, 97.6% in anti-S1/S2 CLIA, 97.2% in anti-RBD ELISA, and 96.1% in anti-RBD+LFI. The sensitivity to detect neutralizing antibodies was ≥85% in anti-S1 ELISA (92.7%), anti-N ECLIA (91.7%), anti-S1/S2 CLIA (90.3%), anti-RBD+LFI (87.9%), and anti-RBD ELISA (85.8%). Sensitivity was 84.1% in anti-N CLIA and 66.2% in anti-N ELISA. The specificity was ≥97% in anti-N CLIA (100%), anti-S1/S2 CLIA (97.7%), and anti-RBD+LFI (97.9%). Specificity was 95.9% in anti-RBD ELISA, 93.0% in anti-N ECLIA, 92% in anti-S1 ELISA, and 65.3% in anti-N ELISA. Diagnostic accuracy measures were consistent among subgroups. CONCLUSIONS: The diagnostic accuracy of serological tests for SARS-CoV-2 antibodies varied remarkably in clinical practice, and the sensitivity to identify patients with previous COVID-19 deviated substantially from the manufacturer's specifications. The data presented here should be considered when using such tests to estimate the infection burden within a specific population and determine the likelihood of protection against re-infection.

A systematic review and metanalysis of diagnostic yield of BAL for detection of SARS-CoV-2.

BACKGROUND: The gold standard for diagnosing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is microbiological confirmation by reverse transcriptase-polymerase chain reaction (RT-PCR)1 most commonly done using oropharyngeal (OP) and nasopharyngeal swabs (NP). But in suspected cases, where these samples are false-negative, bronchoalveolar lavage (BAL) may prove diagnostic. OBJECTIVES: Hence, the diagnostic yield of BAL for detection of SARS-CoV-2 in cases of non-diagnostic upper respiratory tract samples is reviewed. METHODS: Databases such as MEDLINE, Scopus, and Google Scholar were searched using a systematic search strategy. The current study has been in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines and has been registered with the International Prospective Registry of Systematic Reviews (CRD42020224088). RESULTS: 911 records were identified at initial database extraction, of which 317 duplicates were removed and, 596 records were screened for inclusion eligibility. We included total 19 studies in the systematic review, and 17 were included in metanalysis. The pooled estimate of SARS-CoV-2 positivity in BAL was 11% (95%CI: 0.01-0.24). A sensitivity analysis also showed that the results appear to be robust and minimal risk of bias amongst the studies. CONCLUSION: The current study demonstrates that BAL can be used to diagnose additional cases primary disease and superadded infections in patients with severe COVID-19 lower respiratory tract infection.

Accessibility to SARS-CoV-2 swab test during the Covid-19 pandemic: Did age make the difference?

Although COVID-19 affects older people more severely, health policies during the first wave of the pandemic often prioritized younger individuals. We investigated whether age had influenced the access to a diagnostic test for SARS-CoV-2 infection and whether clinical complexity and healthcare resources availability could have impacted such differences. This work included 126,741 Italian participants in the EPICOVID19 web-based survey, who reported having had contacts with known/suspected COVID-19 cases (epidemiological criterion) and/or COVID-19-like signs/symptoms (clinical criterion) from February to June 2020. Data on sociodemographic, medical history and access to SARS-CoV-2 nasopharyngeal swab (NPS) were collected. Logistic regressions estimated the probability of accessing NPS as a function of age and the possible modifying effect of chronic diseases' number and residential areas in such association. A total of 6136 (4.8%) participants had undergone an NPS. Older participants had lower NPS frequencies than the younger ones when reporting epidemiological (14.9% vs. 8.8%) or both epidemiological and clinical criteria (17.5% vs. 13.7%). After adjustment for potential confounders, including epidemiological and clinical criteria, the chance of NPS access decreased by 29% (OR=0.71, 95%CI:0.63-0.79) in older vs. younger individuals. Such disparity was accentuated in areas with greater healthcare resources. In conclusion, in the first wave of the pandemic, age may have affected the access to COVID-19 diagnostic testing, disadvantaging older people.

Acceptability, Usability, and Performance of Lateral Flow Immunoassay Tests for Severe Acute Respiratory Syndrome Coronavirus 2 Antibodies: REACT-2 Study of Self-Testing in Nonhealthcare Key Workers.

BACKGROUND: Seroprevalence studies are essential to understand the epidemiology of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Various technologies, including laboratory assays and point-of-care self-tests, are available for antibody testing. The interpretation of seroprevalence studies requires comparative data on the performance of antibody tests. METHODS: In June 2020, current and former members of the United Kingdom police forces and fire service performed a self-test lateral flow immunoassay (LFIA), had a nurse-performed LFIA, and provided a venous blood sample for enzyme-linked immunosorbent assay (ELISA). We present the prevalence of antibodies to SARS-CoV-2 and the acceptability and usability of self-test LFIAs, and we determine the sensitivity and specificity of LFIAs compared with laboratory ELISA. RESULTS: In this cohort of 5189 current and former members of the police service and 263 members of the fire service, 7.4% (396 of 5348; 95% confidence interval [CI], 6.7-8.1) were antibody positive. Seroprevalence was 8.9% (95% CI, 6.9-11.4) in those under 40 years, 11.5% (95% CI, 8.8-15.0) in those of nonwhite ethnicity, and 7.8% (95% CI, 7.1-8.7) in those currently working. Self-test LFIA had an acceptability of 97.7% and a usability of 90.0%. There was substantial agreement between within-participant LFIA results (kappa 0.80; 95% CI, 0.77-0.83). The LFIAs had a similar performance: compared with ELISA, sensitivity was 82.1% (95% CI, 77.7-86.0) self-test and 76.4% (95% CI, 71.9-80.5) nurse-performed with specificity of 97.8% (95% CI, 97.3-98.2) and 98.5% (95% CI, 98.1-98.8), respectively. CONCLUSIONS: A greater proportion of this nonhealthcare key worker cohort showed evidence of previous infection with SARS-CoV-2 than the general population at 6.0% (95% CI, 5.8-6.1) after the first wave in England. The high acceptability and usability reported by participants and similar performance of self-test and nurse-performed LFIAs indicate that the self-test LFIA is fit for purpose for home testing in occupational and community prevalence studies.

Coronavirus Disease 2019 Serial Testing Among Hospitalized Patients in a Midwest Tertiary Medical Center, July-September 2020.

We implemented serial coronavirus disease 2019 testing for inpatients with a negative test on admission. The conversion rate (negative to positive) on repeat testing was 1%. We identified patients during their incubation period and hospital-onset cases, rapidly isolated them, and potentially reduced exposures. Serial testing and infectiousness determination were resource intensive.

Risk Factors for Testing Positive for Severe Acute Respiratory Syndrome Coronavirus 2 in a National United States Healthcare System.

BACKGROUND: Identifying risk factors for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection could help health systems improve testing and screening strategies. The aim of this study was to identify demographic factors, comorbid conditions, and symptoms independently associated with testing positive for SARS-CoV-2. METHODS: This was an observational cross-sectional study at the Veterans Health Administration, including persons tested for SARS-CoV-2 nucleic acid by polymerase chain reaction (PCR) between 28 February and 14 May 2020. Associations between demographic characteristics, diagnosed comorbid conditions, and documented symptoms with testing positive for SARS-CoV-2 were measured. RESULTS: Of 88 747 persons tested, 10 131 (11.4%) were SARS-CoV-2 PCR positive. Positivity was associated with older age (≥80 vs <50 years: adjusted odds ratio [aOR], 2.16 [95% confidence interval {CI}, 1.97-2.37]), male sex (aOR, 1.45 [95% CI, 1.34-1.57]), regional SARS-CoV-2 burden (≥2000 vs <400 cases/million: aOR, 5.43 [95% CI, 4.97-5.93]), urban residence (aOR, 1.78 [95% CI, 1.70-1.87]), black (aOR, 2.15 [95% CI, 2.05-2.26]) or American Indian/Alaska Native Hawaiian/Pacific Islander (aOR, 1.26 [95% CI, 1.05-1.52]) vs white race, and Hispanic ethnicity (aOR, 1.52 [95% CI, 1.40-1.65]). Obesity and diabetes were the only 2 medical conditions associated with testing positive. Documented fevers, chills, cough, and diarrhea were also associated with testing positive. The population attributable fraction of positive tests was highest for geographic location (35.3%), followed by demographic variables (27.1%), symptoms (12.0%), obesity (10.5%), and diabetes (0.4%). CONCLUSIONS: The majority of positive SARS-CoV-2 tests were attributed to geographic location, demographic characteristics, and obesity, with a minor contribution of chronic comorbid conditions.

SARS-CoV-2 PCR and antibody testing for an entire rural community: methods and feasibility of high-throughput testing procedures.

BACKGROUND: Early in the pandemic, inadequate SARS-CoV-2 testing limited understanding of transmission. Chief among barriers to large-scale testing was unknown feasibility, particularly in non-urban areas. Our objective was to report methods of high-volume, comprehensive SARS-CoV-2 testing, offering one model to augment disease surveillance in a rural community. METHODS: A community-university partnership created an operational site used to test most residents of Bolinas, California regardless of symptoms in 4 days (April 20th - April 23rd, 2020). Prior to testing, key preparatory elements included community mobilization, pre-registration, volunteer recruitment, and data management. On day of testing, participants were directed to a testing lane after site entry. An administrator viewed the lane-specific queue and pre-prepared test kits, linked to participants' records. Medical personnel performed sample collection, which included finger prick with blood collection to run laboratory-based antibody testing and respiratory specimen collection for polymerase chain reaction (PCR). RESULTS: Using this 4-lane model, 1,840 participants were tested in 4 days. A median of 57 participants (IQR 47-67) were tested hourly. The fewest participants were tested on day 1 (n = 338 participants), an intentionally lower volume day, increasing to n = 571 participants on day 4. The number of testing teams was also increased to two per lane to allow simultaneous testing of multiple participants on days 2-4. Consistent staffing on all days helped optimize proficiency, and strong community partnership was essential from planning through execution. CONCLUSIONS: High-volume ascertainment of SARS-CoV-2 prevalence by PCR and antibody testing was feasible when conducted in a community-led, drive-through model in a non-urban area.

Identifying possible surrogate markers of COVID19 as a supplement to diagnostic testing in Upstate New York.

INTRODUCTION: COVID19 has raised concerns for resource allocation across various sectors of healthcare. At the frontlines, emergency departments are required to triage a wide range of acuity and non-specific symptomology. METHODS: This retrospective study aimed to pave the way for more concrete detection and triage of patients by analyzing symptomology, physical findings, diagnostic testing and relevant hospital course of the 458 suspected cases that initially presented to an academic level one trauma center emergency department between March and August 2020. A total of 202 COVID positive cases were analyzed. RESULTS: The most common symptoms were cough (70.63%), fatigue (77%), and shortness of breath (59%). There was a significantly higher percentage of abnormal chest imaging in inpatient groups compared to the ED discharge group (42.86% vs 79%, p < 0.01). Laboratory studies, especially markers of inflammation (CRP, ESR), markers of tissue damage (lactic acid, troponin), and markers of infection were markedly higher and above normal reference ranges in complicated cases (p < 0.01). While there is limited data on the sensitivity and specificity of the current nasopharyngeal PCR test, there was no permutation of symptoms, physical findings, diagnostic testing that was more sensitive than that of the current PCR test calculated at 66.1% in our cohort. CONCLUSION: Laboratory studies that otherwise are more commonly conducted inpatient, including markers of inflammation, tissue damage, and infection, may be useful in disposition planning of ED patients in conjunction with clinical correlation of presentation and chest imaging.

Antibody seroprevalence and rate of asymptomatic infections with SARS-CoV-2 in Austrian hospital personnel.

BACKGROUND: The aims of this study are to determine (i) SARS-CoV-2 antibody positive employees in Austrian trauma hospitals and rehabilitation facilities, (ii) number of active virus carriers (symptomatic and asymptomatic) during the study, (iii) antibody decline in seropositive subjects over a period of around 6 months, (iv) the usefulness of rapid antibody tests for outpatient screening. METHOD: A total of 3301 employees in 11 Austrian trauma hospitals and rehabilitation facilities of the Austrian Social Insurance for Occupational Risks (AUVA) participated in this open uncontrolled prospective cohort study. Rapid lateral flow tests, detecting a combination of IgM and IgM against SARS-CoV-2), two different types of CLIA (Diasorin, Roche), RT-PCR tests and serum neutralization tests (SNTs) were performed. The tests were conducted twice, with an interval of 42.4 ± 7.7 (Min = 30, Max = 64) days. Positive participants were re-tested with CLIA/SNT at a third time point after 188.0 ± 12.8 days. RESULTS: Only 27 out of 3301 participants (0.82%) had a positive antibody test at any time point during the study confirmed via neutralization test. Among positively tested participants in either test, 50.4% did not report any symptoms consistent with common manifestations of COVID-19 during the study period or within the preceding 6 weeks. In the group who tested positive during or prior to study inclusion the most common symptoms of an acute viral illness were rhinitis (21.9%), and loss of taste and olfactory sense (21.9%). Based on the neutralization test as the true condition, the rapid antibody test performed better on serum than whole blood as 84.6% instead of 65.4% could be detected correctly. Concerning both CLIA tests overall the Roche test detected 24 (sensitivity = 88.9%) and the Diasorin test 22 positive participants (sensitivity = 81.5%). In participants with a positive SNT result, a significant drop in neutralizing antibody titre from 31.8 ± 22.9 (Md = 32.0) at T1 to 26.1 ± 17.6 (Md = 21.3) at T2 to 21.4 ± 13.4 (Md = 16.0) at T3 (χ2 = 23.848, df = 2, p < 0.001) was observed (χ2 = 23.848, df = 2, p < 0.001)-with an average time of 42.4 ± 7.7 days between T1 and T2 and 146.9 ± 13.8 days between T2 and T3. CONCLUSIONS: During the study period (May 11th-August 3rd) only 0.82% were tested positive for antibodies in our study cohort. The antibody concentration decreases significantly over time with 14.8% (4 out of 27) losing detectable antibodies.

Preferences Toward COVID-19 Diagnostic Testing Features: Results From a National Cross-Sectional Survey.

PURPOSE: Describe preferences toward COVID-19 testing features (method, location, hypothetical monetary incentive) and simulate the effect of monetary incentives on willingness to test. DESIGN: Online cross-sectional survey administered in July 2020. SUBJECTS: 1,505 nationally representative U.S. respondents. MEASURES: Choice of preferred COVID-19 testing options in discrete choice experiment. Options differed by method (nasal-swab, saliva), location (hospital/clinic, drive-through, at-home), and monetary incentive ($0, $10, $20). ANALYSIS: Latent class conditional logit model to classify preferences, mixed logit model to simulate incentive effectiveness. RESULTS: Preferences were categorized into 4 groups: 34% (n = 517) considered testing comfort (saliva versus nasal swab) most important, 27% (n = 408) were willing to trade comfort for monetary incentives, 19% (n = 287) would only test at convenient locations, 20% (n = 293) avoided testing altogether. Relative to no monetary incentives, incentives of $100 increased the percent of testing avoiders (16%) and convenience seekers (70%) that were willing to test. CONCLUSION: Preferences toward different COVID-19 testing features vary, highlighting the need to match testing features with individuals to monitor the spread of COVID-19.

Diagnostic accuracy of a SARS-CoV-2 rapid antigen test in real-life clinical settings.

BACKGROUND: Laboratory tests are a mainstay in managing the COVID-19 pandemic, and high hopes are placed on rapid antigen tests. However, the accuracy of rapid antigen tests in real-life clinical settings is unclear because adequately designed diagnostic accuracy studies are essentially lacking. OBJECTIVES: The aim of this study was to assess the accuracy of a rapid antigen test in diagnosing SARS-CoV-2 infection in a primary/secondary care testing facility. METHODS: Consecutive individuals presenting at a COVID-19 testing facility affiliated to a Swiss University Hospital were recruited (n = 1465%). Nasopharyngeal swabs were obtained, and the Roche/SD Biosensor rapid antigen test was conducted in parallel with two real-time PCR tests (reference standard). RESULTS: Among the 1465 patients recruited, RT-PCR was positive in 141 individuals, corresponding to a prevalence of 9.6%. The Roche/SD Biosensor rapid antigen test was positive in 94 patients (6.4%), and negative in 1368 individuals (93.4%; insufficient sample material in 3 patients). The overall sensitivity of the rapid antigen test was 65.3% (95% confidence interval [CI] 56.8-73.1), the specificity was 99.9% (95% CI 99.5-100.0). In asymptomatic individuals, the sensitivity was 44.0% (95% CI 24.4-65.1). CONCLUSIONS: The accuracy of the SARS-CoV-2 Roche/SD Biosensor rapid antigen test in diagnosing SARS-CoV-2 infections in a primary/secondary care testing facility was considerably lower compared with the manufacturer's data. Widespread application in such a setting might lead to a considerable number of individuals falsely classified as SARS-CoV-2 negative.

DUAL-energy computed tomography findings in a case of COVID-19.

BACKGROUND: COVID-19 pneumonia has lesions with a decreased blood flow. Dual-energy computed tomography is suitable to elucidate the pathogenesis of COVID-19 pneumonia because it highlights the blood flow changes in organs. We report the dual-energy computed tomography findings of a successfully treated case of COVID-19 pneumonia. CASE PRESENTATION: An obese 49-year-old man with COVID-19 pneumonia was transferred from another hospital on day 11 after onset of illness. Although he was hypoxemic (PaO2/FiO2 = 100), tracheal intubation was not performed after anticipating difficulty in weaning from mechanical ventilation. Prone position therapy and nasal high flow therapy were administered, and the patient was discharged after his condition improved. Dual-energy computed tomography was performed three times during hospitalization, and it revealed improvement in the blood flow defect, unlike plain computed tomography that did not show much improvement. CONCLUSION: Dual-energy computed tomography can assess perfusion in COVID-19 pneumonia in real time and may be able to predict its severity.