Fever without an apparent focus in the young child is a common hospital presentation, and depending on the age and appearance of the child, often results in admission and prescription of antibiotics. Debate over the clinical utility of a nasopharyngeal aspirate (NPA) in this context is not new.
In a recent study performed in the USA, children between 2 and 36 months with fever without an apparent source were tested with NPA polymerase chain reaction (PCR) viral assays. The study compares PCR results among children with no focus with two comparator groups: those with a probable bacterial focus and clinically well children awaiting surgery. Results show that 49% of those with fever no focus, compared with 36% of those with bacterial infection and 31% of afebrile children, have a positive NPA PCR.
Although the authors conclude that the increased detection among children with no focus improves clinical management, we disagree. We believe the high rates of PCR positivity among those unwell with bacterial infection and those completely well should be further evidenced that there is limited benefit in performing a test that adds both cost and an unpleasant experience to the child's admission, with very little information gained. A positive NPA result cannot exclude bacterial infection, nor does it rule in a clinically relevant infection.