A detailed analysis of changes in serum C-reactive protein levels in neonates treated for bacterial infection

A prospective study was undertaken to characterize the rate of increase, time of peak values and rates of decrease in serum concentrations of C-reactive protein (CRP) in a group of infants treated for neonatal bacterial infection. A total of 176 consecutively admitted neonates with birth weight > 1500 g and without mechanical ventilation or central lines in situ, who received antibiotic therapy for suspected bacterial infection, were enrolled. The changes in serum CRP concentration in 60 of 63 infants who had CRP values above 20 mg/l 24-48 h after the beginning of treatment were analysed in detail. Initial increase rates in serum CRP levels of up to 4.5 mg/l per h were documented peak were reached at a mean of 19.5 h after antibiotic therapy had been initiated, but in some patients an increase in serum CRP levels occurred up to 40-48 h after the beginning of treatment. The mean serum half-life of CRP in infected neonates was 21 h (range 11.2-38 h).

In neonates with bacterial infection (defined by a combination of clinical signs and increased C-reactive protein and immature-total quotient values) no differences in the overall pattern nor in any of the particular phases of the C-reactive protein response curves could be observed between neonates with positive (n = 13) or negative blood cultures (n = 47).