Utility of early influenza diagnosis through point-of-care testing in children presenting to an emergency department

Aim: Influenza causes a large burden of disease in children. Point-of-care testing (POCT) can rapidly diagnose influenza with the potential to reduce investigation and hospital admission rates, but information on its use in an Australian setting is limited. Methods: Through a retrospective review of laboratory-confirmed influenza cases presenting at a paediatric emergency department (ED) in 2009, we evaluated children diagnosed by POCT versus standard testing (direct fluorescent antibody, polymerase chain reaction or viral culture) and assessed differences in investigations, admission requirements, length-of-stay (LOS) in ED/hospital and antibiotic/antiviral prescription. The rate of serious bacterial infection was examined. Results: Compared with standard testing (n = 65), children diagnosed by positive POCT (n = 236) had a shorter median hospital LOS by 1 day (P = 0.006), increased antiviral prescription (odds ratio 3.31, P < 0.001) and a reduction in the time to influenza diagnosis (2.4 vs. 24.4 h, P < 0.001); however, a negative POCT result (n = 63) resulted in delayed diagnosis (44.0 h, P = 0.001). POCT did not decrease LOS in ED. Interpretation of reductions in admission and investigations with POCT may be limited by possible confounding. Approximately 4% of influenza patients had a serious bacterial infection; urinary tract infections were commonest (2.7%), but no cerebrospinal fluid cultures were positive. A single positive blood culture was seen among 332 immunocompetent influenza patients. Conclusions: Influenza diagnosis by POCT was quicker and reduced LOS of hospitalised children, whereas negative results delayed diagnosis. Negative POCT should not alter usual investigations if influenza remains suspected. A controlled prospective study during the influenza season is needed to clarify the direct benefits of POCT.