Granulocyte colony-stimulating factor as a marker for bacterial infection in neonates

Objective: To evaluate granulocyte colony-stimulating factor (G-CSF) as an early marker of bacterial or fungal infection in neonates. Study design: We measured G-CSF levels in infants of varying gestational and postnatal ages. We separated the infants into three groups: group 1, positive bacterial or fungal blood culture result; group 2, negative blood culture result but evidence of clinical sepsis; and group 3, negative blood culture result and no or weak evidence: of sepsis. Comparison of mean G-CSF levels by group was accomplished by an analysis of variance. Results: One hundred seventy-six evaluations for sepsis were done for 156 infants with gestational ages ranging from 24 to 43 weeks; 50% of these infants were less than 35 weeks of gestational age. The mean G-CSF levels of groups 1 and 2 were significantly higher than those of group 3. The mean G-CSF level of each group was 2278 pg/ml (group 1), 1873 pg/ml (group 2), and 280 pg/ml (group 3) (p <0.001). On the basis of a cutoff level of 200 pg/ml, the sensitivity of the test was 95%, specificity 73%, positive predictive value 40%, and negative predictive value 99%. Conclusion: G-CSF levels represent a sensitive marker of infection in neonates of all gestational ages.