Routine use of rapid respiratory viral tests in emergency departments (EDs) has limited value for the general public, according to the results of a review and meta-analysis published today in JAMA Internal Medicine.
The review, which evaluated 11 randomized clinical trials (RCTs) involving patients of any age who had an acute respiratory infection (ARI) and visited an ED, found that while rapid viral testing in EDs was associated with higher influenza antiviral use in patients who tested positive, it had no association with overall antibiotic use, length of ED stay, return visits to the ED, or hospitalization rates.
The authors of the study said the results suggest the tests—which are designed to distinguish between viral and bacterial respiratory infections and are recommended by some antimicrobial stewardship guidelines to help reduce unnecessary antibiotic prescribing—should be reserved for patients in whom the results will change treatment.
Tests should be used judiciously
To assess the impact of rapid viral testing in EDs, researchers from Canada, Germany, and the United Kingdom reviewed RCTs published after 1984 that involved the use of ED rapid respiratory virus testing or the awareness of the treating physician of the test results.
The primary outcome was the association with antibiotic prescribing during the ED visit. Secondary outcomes included influenza antiviral use, additional tests (eg, chest x-ray, blood culture, urine culture), length of ED stay, ED return visits, or hospitalization.
Of the 7,157 RCTs identified, 11 involving 6,068 patients (16% adults) were included in the pooled analyses. With high certainty of evidence, those studies showed little or no difference in antibiotic use between rapid viral testing and controls (risk ratio [RR], 0.99; 95% confidence interval [CI], 0.93 to 1.05). Nor was there any difference in antibiotic use by age-group, type of rapid viral test, number of viral targets, or risk of bias.
Although analysis of seven RCTs showed that fewer patients with a positive rapid viral test for flu were prescribed antibiotics, a finding that may suggest more appropriate prescribing in this subgroup, the study authors note that this finding was observed only in studies involving monoplex antigen tests for influenza and not in studies that used the newer molecular multiplex panels that can detect multiple viruses. In addition, it was counterbalanced by more antibiotic prescribing for patients with negative test results.
"Given the absence of benefit of RV [rapid viral] testing on overall antibiotic use, these findings suggest that RV testing should not be routine, but rather should be reserved for patients for whom the testing will change treatment," the authors wrote.
The meta-analysis did show, with moderate certainty of evidence, a 33% increase in antiviral prescribing with rapid viral testing (RR, 1.33; 95% CI, 1.02 to 1.75), along with modest decreases in lower-chest x-ray (RR, 0.88; 95% CI, 0.79 to 0.98) and blood testing (RR, 0.81; 95% CI, 0.69 to 0.97). But there was association with urine testing (RR, 0.95; 95% CI, 0.77 to 1.17), ED length of stay (0 hours; 95% CI, –0.17 to 0.16), return visits (RR, 0.93; 95% CI, 0.79 to 1.08), or hospitalization (RR, 1.01; 95% CI, 0.95 to 1.08)
Given the absence of benefit of RV [rapid viral] testing on overall antibiotic use, these findings suggest that RV testing should not be routine, but rather should be reserved for patients for whom the testing will change treatment.
In an editorial that accompanies the study, journal associate editor and University of Michigan professor Lona Mody, MD, says the findings indicate the evidence for using rapid viral tests to reduce empiric antibiotic use and expensive diagnostic tests remains "underdeveloped."
"Thus, rapid viral tests should be used judiciously," Mody wrote. "Further, there is a need to build high-quality evidence to identify at-risk populations for whom these tests are most informative, efficient, and cost effective."
