ABSTRACT
Previous studies have described RT-LAMP methodology for the rapid detection of SARS-CoV-2 in nasopharyngeal (NP) and oropharyngeal (OP) swab and saliva samples. This study describes the validation of an improved sample preparation method for extraction free RT-LAMP and defines the clinical performance of four different RT-LAMP assay formats for detection of SARS-CoV-2 within a multisite clinical evaluation. Direct RT-LAMP was performed on 559 swabs and 86,760 saliva samples and RNA RT-LAMP on extracted RNA from 12,619 swabs and 12,521 saliva from asymptomatic and symptomatic individuals across healthcare and community settings. For Direct RT-LAMP, overall diagnostic sensitivity (DSe) of 70.35% (95% CI 63.48-76.60%) on swabs and 84.62% (79.50-88.88%) on saliva was observed, with diagnostic specificity (DSp) of 100% (98.98-100.00%) on swabs and 100% (99.72-100.00%) on saliva when compared to RT-qPCR; analysing samples with RT-qPCR ORF1ab CT values of [≤]25 and [≤]33, DSe of 100% (96.34-100%) and 77.78% (70.99-83.62%) for swabs were observed, and 99.01% (94.61-99.97%) and 87.61% (82.69-91.54%) for saliva, respectively. For RNA RT-LAMP, overall DSe and DSp were 96.06% (92.88-98.12%) and 99.99% (99.95-100%) for swabs, and 80.65% (73.54-86.54%) and 99.99% (99.95-100%) for saliva, respectively. These findings demonstrate that RT-LAMP is applicable to a variety of use-cases, including frequent, interval-based testing of saliva with Direct RT-LAMP from asymptomatic individuals that may otherwise be missed using symptomatic testing alone.
ABSTRACT
BackgroundCOVID-19 has placed unprecedented demands on hospitals. A clinical service, COVID Oximetry @home (CO@h) was launched in November 2020 to support remote monitoring of COVID-19 patients in the community. Remote monitoring through CO@h aims to identify early patient deterioration and provide timely escalation for cases of silent hypoxia, while reducing the burden on secondary care. MethodsWe conducted a retrospective service evaluation of COVID-19 patients onboarded to CO@h from November 2020 to March 2021 in the North Hampshire (UK) community led service (a collaboration of 15 GP practices covering 230,000 people). We have compared outcomes for patients admitted to Basingstoke & North Hampshire Hospital who were CO@h patients (COVID-19 patients with home monitoring of SpO2 (n=115)), with non-CO@h patients (those directly admitted without being monitored by CO@h (n=633)). Crude and adjusted odds ratio analysis was performed to evaluate the effects of CO@h on patient outcomes of 30-day mortality, ICU admission and hospital length of stay greater than 3, 7, 14, and 28 days. ResultsAdjusted odds ratios for CO@h show an association with a reduction for several adverse patient outcome: 30-day hospital mortality (p<0.001 OR 0.21 95% CI 0.08-0.47), hospital length of stay larger than 3 days (p<0.05, OR 0.62 95% CI 0.39-1.00), 7 days (p<0.001 OR 0.35 95% CI 0.22-0.54), 14 days (p<0.001 OR 0.22 95% CI 0.11-0.41), and 28 days (p<0.05 OR 0.21 95% CI 0.05-0.59). No significant reduction ICU admission was observed (p>0.05 OR 0.43 95% CI 0.15-1.04). Within 30 days of hospital admission, there were no hospital readmissions for those on the CO@h service as opposed to 8.7% readmissions for those not on the service. ConclusionsWe have demonstrated a significant association between CO@h and better patient outcomes; most notably a reduction in the odds of hospital lengths of stays longer than 7, 14 and 28 days and 30-day hospital mortality.
