Testing for Respiratory Viruses in Children: To Swab or Not to Swab

While most viral respiratory tract infections can be diagnosed clinically, clinicians frequently order tests to identify the specific offending virus. While there has been tremendous growth in the variety, availability, and sophistication of the types of respiratory viral tests, there may have been less critical thought and discussion among frontline clinicians about the clinical utility and specific indications for testing. We summarize the rationale historically used to support respiratory virus testing in children, with a review of the supporting evidence. We outline potential considerations and limitations of the various types of respiratory viral tests and suggest some clinical indications where viral testing may play an important role in clinical management.

The main value of testing for viruses in children who present with a respiratory tract infection is to differentiate between viral and bacterial infections, hopefully facilitating clinical decision making regarding further investigations and the need for antibiotics. We have highlighted commonly cited rationale used to support testing and the generally poor evidence on which to base this rationale. In addition, difficulties with interpretation of respiratory viral testing results include somewhat poor diagnostic test characteristics for some tests, uncertainty regarding true positives and causation of illness, delay in receiving the test result, and the incidence of concurrent bacterial infections or the presence of multiple viruses. We have given some examples of clinical scenarios where respiratory viral testing results could be expected to contribute to more appropriate clinical management decisions.

It is not good enough to "do" just because we "can." We suggest that for many healthy immune-competent children presenting with typical viral respiratory tract symptoms, the diagnosis can be made clinically, and frontline clinicians should think critically before automatically requesting a somewhat uncomfortable, expensive respiratory viral test, the result of which may not contribute to the child's treatment.