December 2nd 2006
ABSTRACT: Because the clinical diagnosis of influenza can be difficult, pediatricians often turn to rapid antigen tests to confirm a clinical suspicion of influenza. However, keep in mind that the predictive values of such tests vary with disease prevalence; despite the favorable sensitivity and specificity of most such tests, their positive predictive value is relatively low early and late in the influenza season. In addition, to gauge the predictive accuracy of a test in a particular setting, consider the degree of clinical suspicion as well as the frequency of influenza in the community at that time. Rapid influenza tests are most often helpful when the likelihood of influenza is intermediate (ie, in the early phase of influenza season when there is very strong clinical suspicion or during the peak of the season when there is moderate clinical suspicion).