Objective: To assess the sensitivity and specificity of neutrophil CD64 as a diagnostic marker for clinical sepsis (based on a hematologic score) and as an additional marker with hematologic parameters for culture-proven sepsis in neonates.
Study design: Prospective observational cohort over 18 months in a single-center neonatal intensive care unit.
Results: Hematologic and CD64 data were available on 1,156 sepsis evaluations done in 684 infants, of which 411 (36%) instances of positive clinical sepsis were identified. The CD64 index for clinical sepsis had an overall area under the receiver operating characteristic curve of 0.71. An optimum CD64 cut point value of 2.19 for late-onset clinical sepsis was calculated with a sensitivity of 78%, a specificity of 59%, and a negative predictive value of 81%. The birth weight-specific CD64 cut point for early onset clinical sepsis was 3.13, 2.34, and 2.05 for very low, low, and normal birth weight, respectively. Neutrophil CD64, in combination with the absolute neutrophil count or the absolute band count, had the highest sensitivity (91%) and specificity (93%), respectively, to diagnose culture-proven sepsis.
Conclusion: We conclude that neutrophil CD64 index can be incorporated with specific hematologic criteria as an additional marker for diagnosis of neonatal sepsis.
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