Patients given a point-of-care test for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection on emergency admission to a U.K. hospital had large reductions in time to results compared with similar patients in a control group diagnosed with centralized laboratory polymerase chain reaction (PCR) tests in a controlled study of 1,054 patients.
"Our findings are the first to suggest the clinical benefits of molecular point-of-care COVID-19 testing in hospitals, demonstrating reduced delays, bed moves, and time in assessment areas, which all lead to better infection control," said study lead author Tristan W. Clark, MRCP, DTM&H, MD, Associate Professor and Honorary Consultant in Infectious Diseases at Southampton General Hospital in the U.K.
The QIAstat-Dx Respiratory SARS-CoV-2 Panel point-of-care test resulted in a range of outcome measures associated with clinical superiority-not just improved time to results. Infection control measures and recruitment into clinical trials were better than in the control group. The study also found that the real-world diagnostic accuracy of the rapid gene panel test was high compared to standard PCR.
The findings are published in The Lancet Respiratory Medicine, where the investigators wrote that, although several rapid molecular platforms capable of testing for SARS-CoV-2 at the point of care had been developed and were all likely to reduce time to results, there had previously been "little evidence for their clinical effect and real-world diagnostic accuracy"-issues the new study was designed to address (2020; doi:https://doi.org/10.1016/S2213-2600(20)30454-9).
Research Findings
Median time to diagnosis was 1.7 hours for the rapid test as compared with 21.3 hours in the control group. There was no significant reduction in specificity or sensitivity. The researchers concluded that such tests could improve infection control by shortening the time infected and non-infected patients could potentially share the same area, by reducing the number of bed changes during hospital stay and giving appropriate treatment sooner.
"Less time spent in assessment areas means that non-infected patients spend less time unknowingly exposed to infected patients and are therefore less likely to acquire nosocomial infection," wrote the authors. There was also less risk of cross-infection to hospital staff-including cleaners, who were less likely to be exposed to heavily contaminated environments.
"We believe that molecular point-of-care tests should be urgently integrated into care pathways to reduce coronavirus transmission within hospitals to prevent the next wave of the pandemic overwhelming health services around the world," Clark stated.
Management of the COVID-19 pandemic had been hampered by long delays associated with centralized laboratory PCR testing, the researchers wrote. Such delays led to poor patient flow and nosocomial transmission. They urged that rapid, accurate tests be adopted.
Study Details
A total of 499 patients were tested with the QIAstat-Dx Respiratory SARS-CoV-2 Panel (which detects SARS-CoV-2 and other respiratory viruses, including influenza) and compared with patients in a PCR-tested control group of 555 patients. Patients were allocated pragmatically and could not be randomized. The groups were similar in distribution of sex, age, and ethnicity.
Patients were 18 years or older presenting to the emergency department or other acute areas of Southampton General Hospital with suspected COVID-19 between March 20 and April 29, 2020 (during the first wave of the SARS-CoV-2 pandemic in the U.K.).
Nose and throat swab samples taken at admission in the point-of-care testing group were assayed with the rapid test panel. Samples from patients in the contemporaneous control group were sent for standard laboratory PCR. The primary outcome was time to results.
A total of 197 (39%) patients in the study arm and 155 (28%) in the control group tested positive for COVID-19. Median time to results was 1.7 hours in the those receiving point-of-care testing and 21.3 hours in the control group.
Statistical analysis controlling for age, sex, time of presentation, and severity of illness also showed that time to results was markedly shorter in the rapid test group than in the control group-with a statistically significantly hazard ratio of over 4,000.
The investigators concluded that point-of-care testing was associated with large reductions in time to results, which could lead to improvements in infection control measures and patient flow compared with centralized laboratory PCR testing, confirmed by a secondary analysis of infection control and diagnostic accuracy.
After testing, patients were transferred to definitive COVID-positive or negative wards within 8 hours in the point-of-care tested group, compared with 28.8 hours in the control group. 13.7 percent of patients in the study group were transferred directly to the correct ward (bypassing assessment areas), but this was not possible for any of the patients in the control group. The mean number of bed moves between admission and final ward arrival was lower with rapid testing-0.9 moves as compared 1.4 moves in the control group.
The QIAstat-Dx Panel tests positive in a single assay if it detects either of the two genes it targets (ORF1b and the E gene). PCR testing was also done in 469 patients in the point-of-care testing group to compare diagnostic accuracy. The rapid test returned positive results for SARS-CoV-2 in 176 of 177 PCR-positive cases (sensitivity 99.4%) and negative results in 288 of 292 PCR-negative cases (specificity 98.6%).
"Recruiting patients into clinical trials remains an international priority throughout this pandemic and is vital to accelerating the search for effective treatments", said Clark, commenting on the finding that rapid testing had boosted trial recruitment. "This is especially true when researchers are investigating the potential of antivirals, which have to be administered at early disease stages to have the greatest benefit."
Comment
Luke SP Moore, PhD, MRCP, from Chelsea and Westminster Hospital NHS Foundation Trust, and the National Institute for Health Research Health Protection Research Unit in Healthcare-Associated Infections and Antimicrobial Resistance at Imperial College London, commented in The Lancet that shorter times to patient placement in an appropriate care area, fewer bed moves, and faster times to enrollment into other COVID-19 clinical trials had all been significant advantages. He emphasized the need for such independent, prospective, controlled, in-situ evaluations of respiratory virus diagnostics.
"We need to push even further for clear analyses of implementation and impact to best understand and leverage the value added from point-of-care platforms during this pandemic and beyond," he wrote.
Peter M. Goodwin is a contributing writer.