Rapid influenza test in young febrile infants for the identification of low-risk patients.

We included 381 febrile infants less than 3 months with a blood culture and a rapid influenza test done as part of study of fever. The prevalence of serious bacterial infections was significantly lower in patients in the positive rapid influenza test (RIT) group (3/113; 2.65%; 95% CI: 0-5.6) than in patients in the negative RIT group (47/268; 17.5%; 95% CI: 13-22.0). No patient with a positive RIT had a positive blood culture (vs. 8 in the negative RIT group, 2.98%, 95% CI: 0.9-5.0) The cerebrospinal fluid culture was positive in 5; all of them had a negative RIT. The use of RIT in the Emergency Department on previously well-appearing febrile young infants without a known source during influenza seasons can help to identify infants with a lower risk of developing serious bacterial infections. Routine blood culture may be no longer necessary in infants with a positive RIT.