Serum amyloid A: an early and accurate marker of neonatal early-onset sepsis

Objectives: To evaluate the accuracy of serum amyloid A (SAA), an acute phase protein in the detection of neonatal early-onset sepsis, by means of a fast automated SAA kit. Study Design: Full-term infants <72 h of age, who had risk factors and/or were suspected of having sepsis, were eligible for study. The levels of SAA were taken at 0, 24 and 48 h post sepsis evaluation. Thirty matched infants served as a control group for comparing SAA concentrations. Results: Of 104 infants eligible for entry to the study, 23 had sepsis and 81 had not sepsis. The SAA levels of the septic group were significantly higher than those of the nonseptic group at 0, 24 and 48 h (P < 0.01 for all time points). In comparison with C-reactive protein (CRP), SAA levels rose earlier and in a sharper manner, had higher levels and returned faster to normal values in infants with early onset sepsis. At 0 h post-sepsis evaluation, serum SAA had an overall better diagnostic accuracy for predicting early onset sepsis than CRP (sensitivity (96 vs 30%), specificity (95 vs 98%), positive predictive value (85 vs 78%), negative predictive value (99 vs 83%), positive likelihood ratio (19 vs 12), and negative likelihood ratio (0.05 vs 0.71). Conclusions: SSA is advocated as an inflammatory marker of neonatal early-onset sepsis.