Human neutrophil lipocalin (HNL) as a diagnostic tool in children with acute infections: A study of the kinetics

Aim: To study the changes in blood of human neutrophil lipocalin (HNL) and C-reactive protein (CRP) during the course of an acute infection in children. Methods: Children (n=92) hospitalized with symptoms and signs of acute infections were included and categorized into five groups, i.e. bacterial infection, suspected bacterial infection, viral infection, suspected viral infection and others. Blood was taken at admittance and the following 3-4 d for the measurement of CRP and HNL. Results: Both CRP and HNL were significantly raised at admittance in bacterial infection as compared to viral infection (p < 0.001). After 25-48 h, 83% of the children with bacterial infections still had raised CRP levels in contrast to 11% having raised HNL levels. The levels of CRP, but not those of HNL, were significantly correlated to days of symptoms before admission. Conclusions: HNL is a promising diagnostic tool in the distinction of acute infections caused by bacteria or virus. The differences in the kinetics of CRP and HNL make HNL a better marker for monitoring antibacterial treatment, since HNL is probably elevated only when an active bacterial infection is at hand.