Clinical Suspicion Of COVID-19 Research Articles

COVID-19 Computed tomography patterns in renal replacement therapy patients.

Lung diseases are common in patients with end stage kidney disease (ESKD), making differential diagnosis with COVID-19 a challenge. This study describes pulmonary chest tomography (CT) findings in hospitalized ESKD patients on renal replacement therapy (RRT) with clinical suspicion of COVID-19. ESKD individuals referred to emergency department older than 18 years with clinical suspicion of COVID-19 were recruited. Epidemiological baseline clinical information was extracted from electronic health records. Pulmonary CT was classified as typical, indeterminate, atypical or negative. We then compared the CT findings of positive and negative COVID-19 patients. We recruited 109 patients (62.3% COVID-19-positive) between March and December 2020, mean age 60 ± 12.5 years, 43% female. The most common etiology of ESKD was diabetes. Median time on dialysis was 36 months, interquartile range = 12-84. The most common pulmonary lesion on CT was ground glass opacities. Typical CT pattern was more common in COVID-19 patients (40 (61%) vs 0 (0%) in non-COVID-19 patients, p < 0.001). Sensitivity was 60.61% (40/66) and specificity was 100% (40/40). Positive predictive value and negative predictive value were 100% and 62.3%, respectively. Atypical CT pattern was more frequent in COVID-19-negative patients (9 (14%) vs 24 (56%) in COVID-19-positive, p < 0.001), while the indeterminate pattern was similar in both groups (13 (20%) vs 6 (14%), p = 0.606), and negative pattern was more common in COVID-19-negative patients (4 (6%) vs 12 (28%), p = 0.002). In hospitalized ESKD patients on RRT, atypical chest CT pattern cannot adequately rule out the diagnosis of COVID-19.

Correlation between Chest Computed Tomography Severity Scores and Age of Adult Patients with Suspected Covid-19 Pneumonia Admitted in Intensive Care Unit of a Tertiary Care Hospital, Bangladesh

In Bangladesh, the second wave of Covid-19 was devastating. Mostly RT-PCR is used to determine the Covid-19 infection. But when test results are delayed, or when there is a clinical suspicion of Covid-19 despite initial negative RT-PCR testing, CT scan of chest was used to detect Covid-19 and Covid-19 severity. This observational cross-sectional study was carried out at Corona dedicated ICU of Bangabandhu Sheikh Mujib Medical College Hospital, Faridpur during February to June, 2021 to observe the HRCT severity score of the patient and its correlation with different ages. A total of 50 patients with clinically suspected Covid-19 cases who were admitted to the Corona dedicated ICU were included in the study. The chest HRCT images of study participants was gathered, CT severity score was calculated by a particular assignment radiologist. Based on this score; Severe disease was mainly seen in the &gt;60 year age group (50%). A significant moderate positive correlation was observed between age and CT chest severity score. With the increasing age the patients were suffering more and being male may increase the risk and put the patient to get admitted in the ICU, and as an alternative of the RT-PCR, CT scan of chest could be useful. Bangabandhu Sheikh Mujib Med. Coll. J. 2023;2(2):77-82

A machine learning tool for the diagnosis of SARS-CoV-2 infection from hemogram parameters.

Monocytes and neutrophils play key roles in the cytokine storm triggered by SARS-CoV-2 infection, which changes their conformation and function. These changes are detectable at the cellular and molecular level and may be different to what is observed in other respiratory infections. Here, we applied machine learning (ML) to develop and validate an algorithm to diagnose COVID-19 using blood parameters. In this retrospective single-center study, 49 hemogram parameters from 12,321 patients with clinical suspicion of COVID-19 and tested by RT-PCR (4239 positive and 8082 negative) were analysed. The dataset was randomly divided into training and validation sets. Blood cell parameters and patient age were used to construct the predictive model with the support vector machine (SVM) tool. The model constructed from the training set (5936 patients) achieved an accuracy for diagnosis of SARS-CoV-2 infection of 0.952 (95% CI: 0.875-0.892). Test sensitivity and specificity was 0.868 and 0.899, respectively, with a positive (PPV) and negative (NPV) predictive value of 0.896 and 0.872, respectively (prevalence 0.50). The validation set model (4964 patients) achieved an accuracy of 0.894 (95% CI: 0.883-0.903). Test sensitivity and specificity was 0.8922 and 0.8951, respectively, with a positive (PPV) and negative (NPV) predictive value of 0.817 and 0.94, respectively (prevalence 0.34). The area under the receiver operating characteristic curve was 0.952 for the algorithm performance. This algorithm may allow to rule out COVID-19 diagnosis with 94% of probability. This represents a great advance for early diagnostic orientation and guiding clinical decisions.

A comparative study of diagnostic performance of COVID-19 Reporting and Data System and computed tomography severity score in clinically suspected COVID-19 patients

Purpose: The aim of this study was to compare the diagnostic performance of COVID-19 Reporting and Data System (CO-RADS) and computed tomography (CT) severity score (CT-SS) in patients with clinically suspected coronavirus disease. Methods: A cross-sectional study was done. Patients presenting to the emergency department with symptoms suspicious for COVID-19 were participated. Patients referred with a positive reverse transcription polymerase chain reaction (RT-PCR) had chest CT evaluation done by CO-RADS and CT-SS, respectively, by an independent investigator. A binomial logistic regression analysis was performed to calculate the sensitivity, specificity, diagnostic accuracy, positive predictive value (PPV), and negative predictive value (NPV) of the two scoring systems in diagnosing COVID infection, considering RT-PCR as the reference standard. Results: A total of 400 cases were evaluated. Two hundred sixty-eight patients with a clinical suspicion of COVID-19 had a positive RT-PCR. The mean duration of symptoms was 5.5 ± 3.4 (range, 1–21 days). The mean CO-RADS and CT-SS scores were 3.7 ± 1.4 (range, 1–5) and 9.1 ± 7.5 (range, 0–28), respectively. Air leaks, including pneumothorax, pneumomediastinum, and surgical emphysema, were observed in six cases. The sensitivity, specificity, PPV, NPV, and diagnostic accuracy of CO-RADS was 93.8, 80, 90.7, 92.1, and 90%, respectively. The sensitivity, specificity, PPV, NPV, and diagnostic accuracy of CT-SS were 95, 76, 86, 89, and 85%, respectively. The area under the curve (AUC) for CO-RADS was 0.943 [95% confidence interval (CI), 0.909–0.976, P &lt; 0.001] and AUC for CT-SS was 0.877 (95% CI, 0.821–0.933, P &lt; 0.001), respectively. The cut-off values of CT-SS and CO-RADS were 7.1 and 4.2, respectively. Conclusion: Both scoring systems had good sensitivity, specificity, and diagnostic accuracy in comparison to RT-PCR test to diagnose COVID-19 infection.

Active cancer as the main predictor of mortality for COVID-19 in oncology patients in a specialized center.

Introduction: The role of the type, stage and status of cancer in the outcome of COVID-19 remains unclear. Moreover, the characteristic pathological changes of severe COVID-19 reveled by laboratory and radiological findings are similar to those due to the development of cancer itself and antineoplastic therapies. Objective: To identify potential predictors of mortality of COVID-19 in cancer patients. Materials and methods: A retrospective and cross-sectional study was carried out in patients with clinical suspicion of COVID-19 who were confirmed for COVID-19 diagnosis by RT-PCR testing at the National Institute of Neoplastic Diseases between April and December 2020. Demographic, clinical, laboratory and radiological data were analyzed. Statistical analyses included area under the curve and univariate and multivariate logistic regression analyses. Results: A total of 226 patients had clinical suspicion of COVID-19, the diagnosis was confirmed in 177 (78.3%), and 70/177 (39.5%) died. Age, active cancer, leukocyte count ≥12.8 × 109/L, urea ≥7.4mmol/L, ferritin ≥1,640, lactate ≥2.0mmol/L, and lung involvement ≥35% were found to be independent predictors of COVID-19 mortality. Conclusion: Active cancer represents the main prognosis factor of death, while the role of cancer stage and type is unclear. Chest CT is a useful tool in the prognosis of death from COVID-19 in cancer patients. It is a challenge to establish the prognostic utility of laboratory markers as their altered values it could have either oncological or pandemic origins.

Electrocardiographic changes and clinical profile of patients hospitalized at a university hospital with clinical suspect of covid-19

The COVID-19 pandemic has been a major challenge for the Brazilian health system since the beginning of 2020. Among the difficulties faced, the predisposing factors for the higher mortality rate due to SARS-COV-2 infection stand out. Electrocardiographic findings point to cardiac alterations that suggest predisposition or complications of COVID-19 associated with greater morbidity. Objective: Identifying electrocardiographic changes and profiling hospitalized patients with clinical suspicion of COVID-19. Methodology: Ongoing cohort study, which included 38 patients admitted to the HDT/UFT between March and July 2020, of both genders, aged from 27 to 94 and with clinical suspicion of COVID-19, who had an electrocardiogram with a report issued by a cardiologist. The study in question was approved by the research ethics committee. Results: There was a predominance of elderly patients with comorbidities (50% hypertensive, 42.1% diabetic, 31.6% obese, 10.5% with chronic lung disease and 5.3% with heart disease). 92.1% of patients were confirmed for COVID-19 (RT- PCR and/or serologic testing). Azithromycin being the most used medication during hospitalization, 28.9% of patients progressed to respiratory failure and orotracheal intubation. Electrocardiographic evaluations in the initial phase of hospitalization showed that 89.5% had sinus rhythm and 10.5% had atrial fibrillation or atrial rhythm. In 13.2% of the cases there were alterations that suggested acute or chronic ischemic involvement, 10.5% alterations in ventricular conduction and 26.1% alterations in ventricular repolarization (QT interval ranging from 100 to 515 ms).

Clinical Characteristics and Management of Patients with a Suspected COVID-19 Infection in Emergency Departments: A European Retrospective Multicenter Study.

Background: Our aim is to describe and compare the profile and outcome of patients attending the ED with a confirmed COVID-19 infection with patients with a suspected COVID-19 infection. Methods: We conducted a multicentric retrospective study including adults who were seen in 21 European emergency departments (ED) with suspected COVID-19 between 9 March and 8 April 2020. Patients with either a clinical suspicion of COVID-19 or confirmed COVID-19, detected using either a RT-PCR or a chest CT scan, formed the C+ group. Patients with non-confirmed COVID-19 (C− group) were defined as patients with a clinical presentation in the ED suggestive of COVID-19, but if tests were performed, they showed a negative RT-PCR and/or a negative chest CT scan. Results: A total of 7432 patients were included in the analysis: 1764 (23.7%) in the C+ group and 5668 (76.3%) in the C− group. The population was older (63.8 y.o. ±17.5 vs. 51.8 y.o. +/− 21.1, p < 0.01), with more males (54.6% vs. 46.1%, p < 0.01) in the C+ group. Patients in the C+ group had more chronic diseases. Half of the patients (n = 998, 56.6%) in the C+ group needed oxygen, compared to only 15% in the C− group (n = 877). Two-thirds of patients from the C+ group were hospitalized in ward (n = 1128, 63.9%), whereas two-thirds of patients in the C− group were discharged after their ED visit (n = 3883, 68.5%). Conclusion: Our study was the first in Europe to examine the emergency department’s perspective on the management of patients with a suspected COVID-19 infection. We showed an overall more critical clinical situation group of patients with a confirmed COVID-19 infection.

How accurate are radiography and computed tomography in the diagnosis of COVID-19?-A Bayesian approach.

The role of radiology in patients with clinical suspicion of COVID-19 is evolving with scientific evidence, but there are differences in opinion on when and how the technique should be used for clinical diagnosis. To estimate the pre-test and post-test probability that a patient has COVID-19 in the event of a positive and/or negative result from chest X-ray and chest computed tomography (CT) radiological studies, comparing with those of real time polymerase chain reaction (RT-PCR) tests. The literature on the sensitivity and specificity of the chest X-ray, chest CT, and RT-PCR was reviewed. Based on these reported data, the likelihood ratios (LR) were estimated and the pre-test probabilities were related to the post-test probabilities after positive or negative results. The chest X-ray has only a confirmatory value in cases of high suspicion. Chest CT analyses showed that when it is used as a general study, it has almost confirmatory value under high clinical suspicion. A chest CT classified with CO-RADS ≥ 4 has almost a diagnostic certainty of COVID-19 even with moderate or low clinical presumptions, and the CO-RADS 5 classification is almost pathognomonic before any clinical presumption. To rule out COVID-19 completely is only possible in very low clinical assumptions with negative RT-PCR and/or CT. Chest X-ray and especially CT are fast studies that have the capacity to report high probability of COVID-19, being a real contribution to the concept of "probable case" and allowing support to be installed in an early and timely manner.

Untargeted saliva metabolomics by liquid chromatography—Mass spectrometry reveals markers of COVID-19 severity

The COVID-19 pandemic is likely to represent an ongoing global health issue given the potential for new variants, vaccine escape and the low likelihood of eliminating all reservoirs of the disease. Whilst diagnostic testing has progressed at a fast pace, the metabolic drivers of outcomes-and whether markers can be found in different biofluids-are not well understood. Recent research has shown that serum metabolomics has potential for prognosis of disease progression. In a hospital setting, collection of saliva samples is more convenient for both staff and patients, and therefore offers an alternative sampling matrix to serum. Saliva samples were collected from hospitalised patients with clinical suspicion of COVID-19, alongside clinical metadata. COVID-19 diagnosis was confirmed using RT-PCR testing, and COVID-19 severity was classified using clinical descriptors (respiratory rate, peripheral oxygen saturation score and C-reactive protein levels). Metabolites were extracted and analysed using high resolution liquid chromatography-mass spectrometry, and the resulting peak area matrix was analysed using multivariate techniques. Positive percent agreement of 1.00 between a partial least squares-discriminant analysis metabolomics model employing a panel of 6 features (5 of which were amino acids, one that could be identified by formula only) and the clinical diagnosis of COVID-19 severity was achieved. The negative percent agreement with the clinical severity diagnosis was also 1.00, leading to an area under receiver operating characteristics curve of 1.00 for the panel of features identified. In this exploratory work, we found that saliva metabolomics and in particular amino acids can be capable of separating high severity COVID-19 patients from low severity COVID-19 patients. This expands the atlas of COVID-19 metabolic dysregulation and could in future offer the basis of a quick and non-invasive means of sampling patients, intended to supplement existing clinical tests, with the goal of offering timely treatment to patients with potentially poor outcomes.

Diagnostic Role of Bronchoalveolar Lavage in Patients with Suspected SARS-CoV-2 Pneumonia and Negative Upper Respiratory Tract Swab: A Systematic Review and Meta-Analysis.

The added role of bronchoalveolar lavage (BAL) in SARS-CoV-2 detection in hospitalized patients with suspected COVID-19 pneumonia and at least one negative nasopharyngeal swab (NPS) has yet to be definitively established. We aimed to provide a systematic review and meta-analysis to summarize data from the literature on the diagnostic yield of BAL in this context. We searched Medline and Embase for all studies reporting outcomes of interest published up to October 2021. Two authors reviewed all titles/abstracts and retrieved the selected full texts according to predefined selection criteria. The summary estimate was derived using the random-effects model. Thirteen original studies, involving 868 patients, were included. The summary estimate of proportions of SARS-CoV-2 positivity in BAL fluid in patients with at least one previous negative NPS was 20% (95% confidence interval [CI]; 11–30%). Moreover, microbiological tests of BAL fluid led to the identification of other pathogens, mainly bacteria, in up to two-thirds of cases. BAL plays a crucial role in the diagnostic work-up of patients with clinical suspicion of COVID-19 and previous negative NPS, as it allowed to detect the infection in a significant proportion of subjects, who would have been otherwise misclassified, with relevant implications in the prevention of disease spread, especially in hospital settings.

Cutaneous Manifestations of COVID-19 in the Lower Limbs: A Narrative Review.

In 2020, the World Health Organization declared the COVID-19 pandemic. This infectious pathology can be associated with different manifestations in different body systems, among which are dermatological lesions. The purpose of this work is to determine the most frequent dermatological signs, in the lower limbs, produced by SARS-CoV-2. To carry this out, a bibliographic search was performed in the following databases: PubMed, SciELO, ScienceDirect, Cochrane Database of Systematic Reviews, and the Google Scholar literature. The inclusion criteria were articles that included confirmed subjects or those with a clinical suspicion of COVID-19, written in the Spanish or English languages, and the results presented clinical manifestations in the lower extremities. Initially, 128 scientific documents were identified and, after reading the title and abstract, 18 articles were selected. The most frequent skin lesions on the lower limbs are acral lesions such as pernio erythema or ischemic lesions, maculopapular rash, petechiae, and erythematous plaques.

Manifestaciones sistémicas y extrapulmonares en la COVID-19

Although fever and respiratory symptoms are the main clinical expression of COVID-19 disease, important extrapulmonary complications that affect the majority of the organs and systems may occur. Multisystemic involvement can mainly be attributed to the generalized location of ACE2 receptors throughout the body, which act as the main point of entry for the virus. Systemic manifestations may occasionally appear before the typical symptoms, although they generally occur later or are sequelae of the disease. Thromboembolic complications are concerning due to their frequency and severity; they are the result of a hypercoagulable state with multiple possible clinical manifestations. Cardiac, neurological, gastrointestinal, renal, endocrine-metabolic, skin, and ocular complications may occur. The manifestations and specific therapeutic aspects of COVID-19 disease in pregnant women as well as implications of the disease on children are discussed. The corresponding tests must be performed in all patients with a clinical suspicion of COVID-19 in order to confirm the diagnosis of the infection. The specific diagnostic tests that are indicative of involvement of different organs are guided based on clinical suspicion. These tests are conducted on an individual basis taking into account the isolation measures required and the severity of each case. Likewise, the corresponding treatment is administered according to criteria that generally similar to those for the general population.

Different performance of three point-of-care SARS-CoV-2 antigen detection devices in symptomatic patients and close asymptomatic contacts: a real-life study

ObjectivesPCR on nasopharyngeal exudates, the cornerstone of the detection of SARS-CoV-2, is time-consuming and commonly unavailable at primary health care centres. Detection of viral nucleocapsid antigens using lateral flow point-of-care tests is helpful for the early triage of patients who attend health care facilities. MethodsThis was a prospective study carried out in clinically suspected cases and close asymptomatic contacts who attended a primary care centre (Madrid, Spain) for SARS-CoV-2 detection. Patients were divided into three 300-patient cohorts (n = 200 symptomatic cases and n = 100 close asymptomatic contacts per cohort). Three antigen detection tests (SGTI-Flex COVID-19 Ag, Panbio COVID-19 Ag Rapid Test Device, and GSD NovaGen SARS-CoV-2 Ag Rapid Test) were used and compared. Paired nasopharyngeal exudates were obtained, one swab for PCR and the other for antigen detection. Each antigen detection test was evaluated on one cohort. ResultsAll tests showed invariably 100% specificity. Sensitivity was 68.9% (95% CI: 55.7–80; SGTI-Flex), 71.1% (95% CI: 55.6–83.6; Panbio), and 84.6% (95% CI: 72–93.1; NovaGen) in clinically suspected patients and 84.6% (95% CI: 54.5–98.1), 33.3% (95% CI: 11.8–61.6), and 55.6% (95% CI: 30.7–78.4) in close asymptomatic contacts, respectively. Sensitivity was systematically higher in samples yielding positive PCR results with Ct ≤ 20. DiscussionWe found considerable test-to-test antigen detection variations among patients with clinical suspicion of COVID-19 and close asymptomatic contacts. Negative antigen results, regardless of the test used, should be confirmed by PCR.

Computed Tomography Findings and Clinico-Epidemiological Aspects of COVID-19 Pneumonia at CHME Luxembourg in Bamako (Mali)

Objective: To describe the CT findings and clinico-epidemiological aspects of coronavirus pulmonary lesions at the Radiology Department of Mother-Child Luxembourg’s Hospital in Bamako, West Africa. Materials and Method: This was a cross-sectional descriptive study over a period of three months (November 2020-January 2021). The study involved all patients with a clinical suspicion of COVID-19 or confirmed cases with suggestive CT scan lesions during this period. No patients without suggestive CT lesions were not included. The variables were age, sex, clinical data, lungs lesions on CT scan and their severity. Results: Out of 202 patients enlisted, the age group 52 - 63 years was more frequent (30.2%), i.e. an average age of 60.43 years (range 23 and 95 years). Men represented 56.4% or a sex ratio of 1.3. Cough was the most common clinical manifestations (26.7%). Major findings were mixed appearance of the lung lesions (45.5%). The peripheral distribution was 57.4% and the bilateral topography was 98%. These lesions were extensive in the majority of our patients with 28.2%. Conclusion: Older people dominated the socio-demographic profile of our series with a predominance of men. Cough was the most observed clinical information. Mixed lesions with peripheral and bilateral distribution dominated the semiological tomodensitometric aspects. By severity, extensive lung lesions were the most commonly observed.

Detection of SARS-CoV-2 RNA in Urine by RT-LAMP: A Very Rare Finding.

Detection of SARS-CoV-2 is routinely performed in naso/oropharyngeal swabs samples from patients via RT-qPCR. The RT-LAMP technology has also been used for viral RNA detection in respiratory specimens with both high sensitivity and specificity. Recently, we developed a novel RT-LAMP test for SARS-CoV-2 RNA detection in nasopharyngeal swab specimens (named, N15-RT-LAMP) that can be performed as a single-tube colorimetric method, in a real-time platform, and as dry-LAMP. To date, there has been very little success in detecting SARS-CoV-2 RNA in urine by RT-qPCR, and the information regarding urine viral excretion is still scarce and not comprehensive. Here, we tested our N15-RT-LAMP on the urine of 300 patients admitted to the Hospital of Salamanca, Spain with clinical suspicion of COVID-19, who had a nasopharyngeal swab RT-qPCR-positive (n = 100), negative (n = 100), and positive with disease recovery (n = 100) result. The positive group was also tested by RT-qPCR for comparison to N15-RT-LAMP. Only a 4% positivity rate was found in the positive group via colorimetric N15-RT-LAMP and 2% via RT-qPCR. Our results are consistent with those obtained in other studies that the presence of SARS-CoV-2 RNA in urine is a very rare finding. The absence of SARS-CoV-2 RNA in urine in the recovered patients might suggest that the urinary route is very rarely used for viral particle clearance.

453. Neutralizing Antibody Responses to SARS-CoV-2 in Professional Soccer Players

BackgroundThe Brazilian Football Confederation (CBF) protocol to control the spread of COVID-19 among professional soccer players is based on four cornerstone measures: (1) Tracing all symptomatic and asymptomatic COVID-19 cases by clinical monitoring and nasal swab SARS-CoV-2 RT-PCR testing up to 3 days before the soccer games; (2) Respiratory isolation of all SARS-CoV-2 positive players for at least 10 days, regardless symptoms; (3) All player with clinical suspicion of COVID-19 were immediately quarantined; (4) If a player became SARS-CoV-2 positive after the game, the other players were allowed to play the next game, if they remained asymptomatic and SARS-CoV-2 RT-PCR negative. Understanding how antibody responses to SARS-CoV-2 evolve can provide insights into therapeutic and testing approaches for COVID-19. In the present study we profile the antibody responses of players up to nine months from a SARS-CoV-2 positive RT-PCR test. MethodsSerum samples were obtained from 955 soccer players, and analyzed at the same laboratory in São Paulo city, in the Hospital Israelita Albert Einstein. It was used the cPas Technology, the sVNT kit for detecting and measuring circulating neutralizing antibodies against the SARS-CoV-2 virus. ResultsNeutralizing antibody was positive for 416 samples (416/955=44%; C.I. 95%= [40%; 47%]). From the 955 soccer players, 454 had RT-PCR+ previously, up to nine months until the neutralizing antibody tests. From this 454 players, 172 (38%) had neutralizing antibody below 20% (C.I. 95% = [34%; 42%]), 30 (7%) between 20% and 30% (C.I. 95% = [5%; 9%]), and e 252 (56%) above 30% (C.I. 95% =[51%; 60%]). Antibody responses to SARS-CoV-2 were significantly higher in individuals RT-PCR+ (Table 1). There was no difference between the neutralizing antibody responses status to SARS-CoV-2 and the time between the RT-PCR+ and the neutralizing antibody test (p-value = 0.423; Figures 1 and 2, Table 2).Table 1. Neutralizing antibody responses to SARS-CoV-2. Figure 1. Scatter plot with Time between RT-PCR+ and neutralizing antibody (days) versus Neutralizing antibody levels. Table 2. Time between RT-PCR+ and neutralizing antibody (days) versus Neutralizing antibody levels. ConclusionThis study found neutralizing activity of infection against SARS-CoV-2 in 63% RT-PCR+ individuals, but only in 26% in RT-PCR(-) players. Level of neutralizing antibody responses maintained stable until up to nine months after a RT-PCR+. Figure 2. Percentage of soccer players at each antibody level (below 20%, between 20% and 30%, and above 30%) versus time between the positive RT-PCR test and neutralizing antibody test (days). Disclosures All Authors: No reported disclosures

Limited diagnostic utility of SARS-CoV-2 serologic testing in symptomatic PCR negative patients

BackgroundGuidelines from the CDC and the IDSA suggest the use of serologic testing to support the diagnosis of COVID-19 in individuals with high clinical suspicion that repeatedly test negative by diagnostic methods. Given that variability in specimen type, collection technique, and time from symptoms all reduce the sensitivity of molecular methods for SARS-CoV-2. The routine use of serology to diagnose and manage patients with symptoms concerning COVID-19 is tempting, despite limited studies in the literature supporting this approach. Here, we assessed the utility of serology testing for diagnosing SARs-CoV-2 in symptomatic, PCR-negative patients.MethodsRemnant EDTA plasma specimens were obtained from 393 patients with clinical suspicion for COVID-19 and a negative SARs-COV-2 RNA test by the nasopharyngeal swab. The specimens were analyzed for SARs-CoV-2 IgG on an Abbott Architect i2000 (Abbott diagnostic). Patient information and symptoms adjudication were obtained from patient electronic health records.Results14 of 393 patients were positive for antibodies to SARS-CoV-2 (seropositivity rate of 3.6%), 6 of which were from patients with previous RT-PCR-confirmed COVID-19 infection. Among patients without previously diagnosed COVID-19, the seropositivity rate in symptomatic patients was 1.2% (2/171), in patients with altered mental status was 4.3% (2/46), and in asymptomatic patients with no known previous COVID-19 diagnoses was 2.6% (4/170). The seropositivity rate among symptomatic patients presenting ≥ 14 days after symptom onset was 0% (0/67), 7-13 days was 5% (1/20), and for patients < 7 days, was 2.1% (1/47). Among the 4 patients with AMS that were serologically positive, 2 were previously diagnosed by PCR.ConclusionThere is a low diagnostic utility of SARS-COV-2 serological testing for identifying novel cases of acute SARS-CoV-2 infections in the ED after a negative PCR test.

Diagnostic accuracy and inter-observer agreement with the CO-RADS lexicon for CT chest reporting in COVID-19

PurposeTo measure the diagnostic accuracy and inter-observer agreement with the use of COVID-19 Reporting and Data System (CO-RADS) for detection of COVID-19 on CT chest imaging.MethodsThis retrospective study included 164 consecutive patients with clinical suspicion of COVID-19 in whom a CT chest examination was performed at a single institution between April 2020 and July 2020. Of them, 101 patients was RT-PCR positive for COVID-19. Six readers with varying radiological experience (two each of chest radiologists, general radiologists, and radiologists in training) independently assigned a CO-RADS assessment category for each CT chest study. The Fleiss’ K was used to quantify inter-observer agreement. The inter-observer agreement was also assessed based on the duration of onset of symptoms to CT scan. ROC curve analysis was used to determine the diagnostic accuracy of CO-RADS. The area under curve was calculated to determine the reader accuracy for detection of COVID-19 lung involvement with RT-PCR as reference standards. The data sets were plotted in ROC space, and Youden’s J statistic was calculated to determine the threshold cut-off CO-RADS category for COVID-19 positivity.ResultsThere was overall moderate inter-observer agreement between all readers (Fleiss’ K 0.54 [95% CI 0.54, 0.54]), with substantial agreement among chest radiologists (Fleiss’ K 0.68 [95% CI 0.67, 0.68]), general radiologists (Fleiss’ K 0.61 [95% CI 0.61, 0.61]), and moderate agreement among radiologists-in-training (Fleiss’ K 0.56 [95% CI 0.56, 0.56]). There was overall moderate inter-observer agreement in early disease (stages 1 and 2), with cumulative Fleiss’ K 0.45 [95% CI 0.45, 0.45]). The overall AUC for CO-RADS lexicon scheme to accurately diagnose COVID-19 yielded 0.92 (95% CI 0.91, 0.94) with strong concordance within and between groups, of chests radiologists with AUC of 0.91 (95% CI 0.88, 0.94), general radiologists with AUC 0.96 (95% CI 0.94, 0.98), and radiologists in training with AUC of 0.90 (95% CI 0.87, 0.94). For detecting COVID-19, ROC curve analysis yielded CO-RADS > 3 as the cut-off threshold with sensitivity 90% (95% CI 0.88, 0.93), and specificity of 87% (95% CI 0.83, 0.91).ConclusionReaders across different levels of experience could accurately identify COVID-19 positive patients using the CO-RADS lexicon with moderate inter-observer agreement and high diagnostic accuracy.

Low utilisation of bronchoscopy to assess COVID-19 respiratory infection: a multicenter experience

ObjectiveFor the diagnosis of COVID-19, the yield of nasopharyngeal (NP) swabs is unclear, and bronchoalveolar lavage (BAL) is obtained to confirm the diagnosis. We assessed the utilisation of bronchoscopy for...

Use of the FebriDx point-of-care test for the exclusion of SARS-CoV-2 diagnosis in a population with acute respiratory infection during the second (COVID-19) wave in Italy

ObjectiveEvaluate the real-world accuracy of Myxovirus resistance protein A (MxA) detected by the rapid, point-of-care FebriDx test during the second-wave pandemic in Italy in patients with acute respiratory infection (ARI) and a clinical suspicion of COVID-19. Design and methodsProspective, observational, diagnostic accuracy study whereby hospitalized patients with ARI were consecutively enrolled in a single tertiary care center in Italy from August 1, 2020 to January 31, 2021. ResultsCOVID-19 was diagnosed in 136/200 (68.0%) patients and Non-COVID-19 was diagnosed in 64/200 (32.0%) patients. COVID-19 patients were younger and had a lower Charlson comorbidity index compared to Non-COVID-19 patients (p < 0.001). Concordance between FebriDx, MxA and rt-PCR for SARS-CoV-2 (gold standard) was good (k 0.93, 95% CI 0.87–0.99). Overall sensitivity and specificity were 97.8% [95% CI 93.7–99.5] and 95.3% [95% CI 86.9%–99.0%], respectively. FebriDx demonstrated a negative predictive value of 95.3% (95% CI 86.9–99.0) for an observed disease prevalence of 68%. ConclusionsFebriDx MxA showed high diagnostic accuracy to identify COVID-19 and could be considered as a real-time triage tool to streamline the management of suspected COVID-19 patients. FebriDx also detected bacterial etiology in Non-COVID-19 patients suggesting good performance to distinguish bacterial from viral respiratory infection.