Earlier this week, we reported on the current rates of influenza-like illness (ILI), based on data from roughly one million patient visits on the athenahealth network. That report showed a steep increase in ILI rates for the week ending Saturday, December 13 (see previous post). It’s not certain that this season will be as severe as that of 2012-2013 (data for pediatrics suggests that is a real possibility); however, providers are testing for flu more consistently than previous years, and prescribing antivirals more often.
Our data shows that the number of flu tests ordered, per patient visit in which ILI is diagnosed, has risen each of the past two years (Figure 1, graph A). This season, providers are ordering flu tests at a rate of 0.53 tests per visit with an ILI diagnosis, compared to 0.37 for last season and 0.34 for 2012-2013. (Note: There can be multiple tests per patient visit, e.g. Type A and B.)