‘No utility’ in retesting patients for SARS-CoV-2 when first test is negative
Few patients at one Chicago institution who originally tested negative for SARS-CoV-2 tested positive the second time around, according to recent data.
The results, presented virtually during the Society for Healthcare Epidemiology of America Spring Conference, suggest there is no clinical reason to routinely retest patients for the virus, Antigone Kraft, MD, a pediatric resident at the University of Chicago Medicine, told Healio Primary Care.
“At the time of the study, testing was still relatively new and we wanted to look at the utility of double testing given that the number of available tests was still something being worked on,” Kraft said. “We also were interested in looking at this problem in terms of analyzing how to apply infection control precautions."
Earlier in the pandemic, the researchers noted that “a concern for false negative nasopharyngeal testing for SARS-CoV-2 at the onset of illness initially led to a policy of retesting inpatients” at their institution. All inpatients with symptoms of COVID-19 were tested upon admission. Those who continued to have undiagnosed symptoms were retested after 48 hours.
For the current analysis, Kraft and colleagues examined data on 14,683 SARS-CoV-2 tests that were performed at the institution from March 17, 2020, to May 10, 2020. Overall, 2,283 patients tested positive for COVID-19, according to the researchers.
Among them, Kraft and colleagues reported that only 19 (0.01%) initially tested negative. Few of these patients, they noted, presented early in the disease course (median of 6 days). The age of these patients ranged from 30 to 86 years, their BMI ranged from 20.7 kg/m2 to 50.3 kg/m2 and their most common symptoms were fever and dyspnea. In addition, most of these patients were men and had at least one comorbidity (most frequently hypertension) and consistent bilateral bibasilar ground glass opacities on CT or chest X-rays when tested again.
“Our study helped support our institution in choosing to only test patients once for COVID‐19, which helped expedite admissions and triage infection control precautions," Kraft said. “False negative testing is such a small portion of testing that there is no utility in retesting patients.”