Accuracy of Rapid Point-of-Care Antibody Test in patients with suspected or confirmed COVID-19

ObjectivesTo assess the real-world diagnostic accuracy of the Livzon point-of-care rapid test for antibodies to SARS-COV-2 DesignProspective cohort study SettingDistrict general hospital in England Participants173 Patients and 224 hospital staff with a history of COVID-19 symptoms, and who underwent PCR and/or reference antibody testing for COVID-19. InterventionsThe Livzon point-of-care (POC) lateral flow immunoassay rapid antibody test (IgM and IgG) was conducted at least 7 days after onset of symptoms and compared to the composite reference standard of PCR for SARS-COV-2 plus reference laboratory testing for antibodies to SARS-COV-2. The SARS-CoV-2 RT-PCR was tested using the available molecular technology during the study time (PHE laboratories, GeneXpert(R) system Xpert, Xpress SARS-CoV-2 and Source bioscience laboratory). All molecular platforms/assays were PHE/NHSE approved. The reference antibody test was the Elecsys Anti-SARS-CoV-2 assay (Roche diagnostics GmBH). Main outcome measuresSensitivity and specificity of the rapid antibody test ResultsThe reference antibody test was positive in 190/268 (70.9%) of participants with a history of symptoms suggestive of COVID-19; in the majority (n=312) the POC test was taken 35 days or more after onset of symptoms. The POC antibody test had an overall sensitivity of 90.1% (292/328, 95% CI 86.3 - 93.1) and specificity of 100% (68/68, 95% CI 94.7 - 100) for confirming prior SARS-CoV-2 infection when compared to the composite reference standard. Sensitivity was 97.8% (89/92, 95% CI 92.3% to 99.7%) in participants who had been admitted to hospital and 84.4% (124/147, 95% CI 77.5% to 89.8%) in those with milder illness who had never been seen in hospital. ConclusionsThe Livzon point-of-care antibody test had comparable sensitivity and specificity to the reference laboratory antibody test, so could be used in clinical settings to support decision-making about patients presenting with more than 10 days of symptoms of COVID-19. What is already known on this topic- Presence of IgG and IgM antibodies to SARS-COV-2 indicates that the person was infected at least 7 days previously and is usually no longer infectious. - Rapid point-of-care tests for antibodies to SARS-COV-2 are widely available, cheap and easy to use - Preliminary evaluations suggested that rapid antibody tests may have insufficient accuracy to be useful for testing individual patients. What this study adds- The rapid point-of-care test for antibodies to SARS-COV-2 was 90.1% sensitive and 100% specific compared to reference standards for prior infection with COVID-19. - This is comparable to reference antibody tests - The point-of-care test evaluated in this study could be used to support clinical decision-making in real time, for patients presenting with symptoms of possible COVID-19 with at least 10 days of symptoms.

Predictors of adverse outcome in patients with suspected COVID-19 managed in a virtual hospital setting: a cohort study

ObjectiveIdentify predictors of adverse outcome in a Virtual Hospital (VH) setting for COVID 19. DesignReal-world prospective observational study. SettingVirtual hospital remote assessment service in West Hertfordshire NHS Trust, UK. ParticipantsPatients with suspected COVID-19 illness enrolled directly from the community (post-accident and emergency (A&E) or medical intake assessment) or post-inpatient admission. Main outcome measureDeath or (re-)admission to inpatient hospital care over 28 days. Results900 patients with a clinical diagnosis of COVID-19 (455 referred from A&E or medical intake and 445 post-inpatient) were included in the analysis. 76 (8.4%) of these experienced an adverse outcome (15 deaths in admitted patients, 3 deaths in patients not admitted, and 58 additional inpatient admissions). Predictors of adverse outcome were increase in age (OR 1.04 [95%CI: 1.02, 1.06] per year of age), history of cancer (OR 2.87 [95%CI: 1.41, 5.82]), history of mental health problems (OR 1.76 [95%CI: 1.02, 3.04]), severely impaired renal function (OR for eGFR <30 = 9.09 [95%CI: 2.01, 41.09]) and having a positive SARS-CoV-2 PCR result (OR 2.0 [95% CI: 1.11, 3.60]). ConclusionsThese predictors may help direct intensity of monitoring for patients with suspected or confirmed COVID-19 who are being remotely monitored by primary or secondary care services. Further research is needed to identify the reasons for increased risk of adverse outcome associated with cancer and mental health problems. ARTICLE SUMMARYO_ST_ABSStrengths and limitations of this studyC_ST_ABSO_LIThe study uses anonymised data from all patients registered for the virtual hospital between 17/03/20 and 17/05/20, and therefore selection bias is not an issue. C_LIO_LIAt the time of this study, this was the only service providing remote follow-up for patients with suspected COVID-19 in the area, and therefore our findings are likely to be relevant to primary care patients receiving remote follow-up. C_LIO_LIWe were able to collect reliable data on a wide range of clinical and demographic features, and reliably follow all patients for the primary outcome for at least two weeks following their discharge from the VH. C_LIO_LIWe were not able to extract detailed symptom or clinical examination data, and there were significant amounts of missing data for some variables. C_LIO_LIOur study is likely underpowered to detect all predictors, especially in the analysis of our two sub-groups C_LI

What is the efficacy and safety of rapid exercise tests for exertional desaturation in Covid-19: A rapid review protocol

BackgroundEven when resting pulse oximetry is normal in the patient with acute Covid-19, hypoxia can manifest on exertion. We sought to summarise the literature on the performance of different rapid tests for exertional desaturation. Research questionWhat tests have been formally evaluated for the rapid assessment of exertional hypoxia? What is the evidence for their accuracy, practicability and safety in the context of suspected acute Covid-19? To what extent will these tests help identify patients with evidence of either silent or hidden hypoxia leading to earlier recognition of those at risk of severe outcomes? MethodWe aim to review three independent searches of AMED, CINAHL, EMBASE MEDLINE, Cochrane and PubMed using LitCovid, Scholar and Google databases until 24th September 2020. Screening, data abstraction, and quality appraisal of full-text papers will be completed independently by two reviewers including a topic expert and a review expert. Studies will be tabulated and assessed for risk of bias using QUADAS 2 tool. DiscussionThis rapid review aims to produce key findings relevant to the assessment of exertional desaturation in patients with suspected Covid-19. Establishing a validated tool to assess exertional desaturation will help to ensure that future research on this topic can be undertaken in a consistent way. An exertional desaturation test should be used in combination with a comprehensive clinical evaluation and only on patients whose resting oximetry reading is 96% or above unless in a supervised care setting. It should be terminated if the patient experiences adverse effects.

Early prognostication of COVID-19 to guide hospitalisation versus outpatient monitoring using a point-of-test risk prediction score

IntroductionRisk factors of adverse outcomes in COVID-19 are defined but stratification of mortality using non-laboratory measured scores, particularly at the time of pre-hospital SARS-CoV-2 testing, is lacking. MethodsMultivariate regression with bootstrapping was used to identify independent mortality predictors in a derivation cohort of COVID-19 patients. Predictions were externally validated in a large random sample of the ISARIC cohort (N=14,231) and a smaller cohort from Aintree (N=290). Results983 patients (median age 70, IQR 53-83; in-hospital mortality 29.9%) were recruited over an 11-week study period. Through sequential modelling, a 5-predictor score termed SOARS (SpO2, Obesity, Age, Respiratory rate, Stroke history) was developed to correlate COVID-19 severity across low, moderate and high strata of mortality risk. The score discriminated well for in-hospital death, with area under the receiver operating characteristic values of 0.82, 0.80 and 0.74 in the derivation, Aintree and ISARIC validation cohorts respectively. Its predictive accuracy (calibration) in both external cohorts was consistently higher in patients with milder disease (SOARS 0-1), the same individuals who could be identified for safe outpatient monitoring. Prediction of a non-fatal outcome in this group was accompanied by high score sensitivity (99.2%) and negative predictive value (95.9%). ConclusionThe SOARS score uses constitutive and readily assessed individual characteristics to predict the risk of COVID-19 death. Deployment of the score could potentially inform clinical triage in pre-admission settings where expedient and reliable decision-making is key. The resurgence of SARS-CoV-2 transmission provides an opportunity to further validate and update its performance.