About rapid flu tests… (Re-post)

I’m sure that many of you are seeing significant volumes in your Emergency Departments. Certainly a lot of it is being driven by flu/concerns about flu/rumors about flu etc,. Here are a few things I want you to remember;

In a meta-analysis of 60 studies of rapid influenza antigen tests in children, the pooled sensitivity of rapid influenza antigen tests was 66.6 percent (95% CI 61.6-71.7 percent) and the pooled specificity was 98.2 percent (95% CI 97.5-99 percent) – adult sensitivity is about 54% for reference. This means that it has a good positive predictive value, but a fair negative predictive value.
Supplies of Influenza A/B rapid antigen kits will deplete quickly
Restrict the use of the rapid antigen test to those situations when it will change your patient management. Thus, if you are going to start antivirals because the patient is high-risk, and it is within 48 hours – then test. Read the CDC’s web site on antivirals for comprehensive information. In short, antivirals are for immunocompromised, chronic pulmonary disease, the young, the old and pregnant women.
If you are doing the test as the part of a workup of a febrile neonate or an immunocompromised child then go ahead and test.
If you need a highly sensitive and can wait (admitting a child for instance) get the respiratory PCR test for influenza A/B. It sometimes comes as a part of a panel.