Evaluation of neutrophilic CD64, interleukin 10 and procalcitonin as diagnostic markers of early- and late-onset neonatal sepsis.

The assay of infection markers can improve diagnostic sensitivity in neonatal sepsis. We determined the levels of neutrophilic CD64 (nCD64), procalcitonin (PCT) and interleukin 10 (IL-10) in infants with neonatal sepsis. Forty-nine newborn infants who met the criteria of sepsis were subjected to a routine sepsis evaluation as well as measurement of PCT and IL-10 levels and nCD64 expression. Of these 49 'infected' infants, 16 had a positive blood culture (culture-positive sepsis) and 33 infants were diagnosed to have clinical sepsis with negative blood cultures (culture-negative sepsis). Another 49 healthy newborn infants were included as a control group. The sensitivity, specificity, positive predictive value and negative predictive value of PCT, IL-10 and nCD64 for the diagnosis of sepsis were determined. IL-10 had the highest sensitivity of 92% and specificity of 84% using a cut-off of > or =17.3 pg/ml. For PCT, the highest sensitivity of 65% and specificity of 60% were found at a cut-off value of > or =36.4 pg/ml. nCD64 had a maximal sensitivity of 92% and specificity of 71% at a cut-off value of 2.6%. Combinations of different markers may improve the sensitivity and specificity of biomarker tests. We found that the best combination was IL-10 and nCD64, which together provided sensitivity of 95% and specificity of 83%, and a negative predictive value of 86%.