Combined RT-PCR and Host Response Point-of-Care Testing in Patients Hospitalised with Suspected COVID-19: A Prospective Diagnostic Accuracy Study.

INTRODUCTION: RT-PCR has suboptimal sensitivity for the diagnosis of COVID-19. A composite reference standard comprising RT-PCR plus radiological and clinical features has been recommended for diagnostic accuracy studies. The FebriDx finger prick point-of-care test detects an antiviral host response protein (MxA) in 10 min. We evaluated the diagnostic accuracy of FebriDx and RT-PCR compared to a composite reference standard. METHODS: Adults presenting to hospital with suspected COVID-19 were tested by FebriDx and RT-PCR. A composite reference standard was used to classify patients as having COVID-19 based on RT-PCR positivity, or RT-PCR negativity with COVID-19 radiological findings or other clinical criteria. Measures of accuracy were calculated for MxA alone, RT-PCR alone, and both combined. This study is registered with the ISRCTN (ISRCTN14966673) and has completed. RESULTS: A total of 478 patients were tested, with valid results in 475. Of these 475 patients, 222 (46.7%) were classified as having COVID-19; 192 (40.4%) were RT-PCR positive, and 30 (6.3%) were RT-PCR negative and diagnosed on radiological/clinical criteria. Sensitivity of FebriDx MxA vs the composite reference standard was 186/222 (83.8%, 95% CI 78.3-88.4) and was similar to the sensitivity of RT-PCR (192/222 (86.5%, 95% CI 81.3-90.7), (difference of 2.7%, 95% CI - 3.9 to 9.3, p = 0.42). The sensitivity of combined FebriDx and RT-PCR was 208/222 (93.7%) which was superior to both RT-PCR alone (difference of 9.9, 95% CI 4.1-15.9; p = 0.001) and FebriDx MxA alone (difference of 7.2, 95% CI 1.6-12.9; p = 0.011). CONCLUSION: Sensitivity of combined FebriDx and RT-PCR testing was superior to each alone for the detection of COVID-19 in hospital and may improve infection control and treatment decisions.

Clinical impact of molecular point-of-care testing for suspected COVID-19 in hospital (COV-19POC): a prospective, interventional, non-randomised, controlled study.

BACKGROUND: The management of the COVID-19 pandemic is hampered by long delays associated with centralised laboratory PCR testing. In hospitals, these delays lead to poor patient flow and nosocomial transmission. Rapid, accurate tests are therefore urgently needed in preparation for the next wave of the pandemic. METHODS: We did a prospective, interventional, non-randomised, controlled study of molecular point-of-care testing in patients aged 18 years or older presenting with suspected COVID-19 to the emergency department or other acute areas of Southampton General Hospital during the first wave of the pandemic in the UK. Nose and throat swab samples taken at admission from patients in the point-of-care testing group were tested with the QIAstat-Dx Respiratory SARS-CoV-2 Panel. Samples taken from patients in a contemporaneous control group were tested by laboratory PCR. The primary outcome was time to results in the full cohort. This study is registered with ISRCTN (ISRCTN14966673) and is completed. FINDINGS: Between March 20 and April 29, 2020, 517 patients were assessed for eligibility, of whom 499 were recruited to the point-of-care testing group and tested by the QIAstat-Dx Respiratory SARS-CoV-2 Panel. 555 contemporaneously identified patients were included in the control group and tested by laboratory PCR. The two groups were similar with regard to the distribution of sex, age, and ethnicity. 197 (39%) patients in the point-of-care testing group and 155 (28%) in the control group tested positive for COVID-19 (difference 11·5% [95% CI 5·8-17·2], p=0·0001). Median time to results was 1·7 h (IQR 1·6-1·9) in the point-of-care testing group and 21·3 h (16·0-27·9) in the control group (difference 19·6 h [19·0-20·3], p<0·0001). A Cox proportional hazards regression model controlling for age, sex, time of presentation, and severity of illness also showed that time to results was significantly shorter in the point-of-care testing group than in the control group (hazard ratio 4023 [95% CI 545-29 696], p<0·0001). INTERPRETATION: Point-of-care testing is associated with large reductions in time to results and could lead to improvements in infection control measures and patient flow compared with centralised laboratory PCR testing. FUNDING: University Hospitals Southampton NHS Foundation Trust.

Clinical characteristics, symptoms and outcomes of 1054 adults presenting to hospital with suspected COVID-19: A comparison of patients with and without SARS-CoV-2 infection.

OBJECTIVES: Most reports describing the characteristics of patients hospitalised with COVID-19 lack a comparator group. We compared clinical characteristics, symptoms, and outcomes of adults presenting to hospital during the pandemic first wave, who tested positive and negative for SARS-CoV-2. METHODS: Detailed patient data was obtained from a large, controlled, non-randomised trial of molecular point-of-care testing versus laboratory RT-PCR for SARS-CoV-2 in adults presenting to a large UK hospital with suspected COVID-19. RESULTS: 1054 patients were included: 352 (33.4%) tested positive and 702 (66.6%) negative. 13.4% (47/352) COVID-19-positive patients had COPD versus 18.7% (131/702) of COVID-19-negative patients (difference=5.3% [95%CI -9.7% to -0.5%], p = 0.0297). 5.7% (20/352) of COVID-19-positive patients were smokers versus 16.5% (116/702) of negative patients (difference=-10.8% [-14.4% to -7.0%], p = 0.0001). 70.5% (248/352) of COVID-19-positive patients were White-British versus 85.5% (600/702) of negative patients (difference=-15.0% [-20.5% to -9.7%], p<0.0001). 20.9% (39/187) of COVID-19-positive patients were healthcare workers versus 5.2% (15/287) of negative patients (p<0.0001). Anosmia was reported in 33.1% (47/142) versus 8.8% (19/216) of COVID-19-positive and negative patients respectively (p<0.0001). Non-SARS-CoV-2 respiratory viruses or atypical bacteria were detected in 2.5% (5/197) of COVID-19 patients versus 7.9% (24/302) of COVID-19-negative patients (p = 0.0109). Hospitalisation duration and 30-day-mortality were higher in COVID-19 patients and invasive ventilation was more frequent (11.1% vs 2.8%, p<0.0001), and longer (14.5 vs 4.7 days, p = 0.0015). CONCLUSIONS: There were substantial differences between patients with and without COVID-19 in terms of ethnicity, healthcare worker-status, comorbidities, symptoms, and outcomes. These data can inform healthcare planning for the next phase of the pandemic.

Diagnostic accuracy of the FebriDx host response point-of-care test in patients hospitalised with suspected COVID-19.

INTRODUCTION: Management of the COVID-19 pandemic is hampered by long delays associated with centralised laboratory PCR testing. In hospitals this leads to poor patient flow and nosocomial transmission and so rapid, accurate diagnostic tests are urgently required. The FebriDx is a point-of-care test that detects an antiviral host response protein in finger prick blood within 10 min, but its accuracy for the identification of COVID-19 is unknown. METHODS: We performed a real-world diagnostic accuracy study of FebriDx in hospitalised patients during the first wave of the pandemic. Measures of diagnostic accuracy were calculated based on FebriDx results compared to the reference standard of SARS-CoV-2 PCR on combined nose and throat swabs. A multivariable predictive model including FebriDx, age, sex, and clinical characteristics was developed and underwent internal validation. RESULTS: FebriDx was performed on 251 patients and gave a valid result in 248. 118 of 248 (48%) were PCR positive for COVID-19. FebriDx results were available after 10 min compared with 1.7 (1.6 to 2.1) hours with point-of-care PCR testing and 23.4 (17.2 to 31.1) hours with laboratory PCR testing. Sensitivity of FebriDx for the identification of COVID-19 was 93% (110/118; 95% CI 87 to 97%) and specificity was 86% (112/130; 95%CI 79 to 92%). Positive and negative likelihood ratios were 6.73 (95%CI 4.37 to 10.37) and 0.08 (95%CI 0.04 to 0.15) respectively. In the multivariate model age, sex and other clinical features did not contribute significantly to the effect of the FebriDx result in distinguishing patients with and without COVID-19. CONCLUSIONS: During the first wave of the pandemic, FebriDx had high accuracy for the identification of COVID-19 in hospitalised adults and could be deployed as a front door triage tool. TRIAL REGISTRATION: ISRCTN14966673.