Plasma myeloperoxidase enzyme assay in cases of neonatal sepsis

Background: Myeloperoxidase (MPO) is a heme enzyme of azurophilic granules in neutrophils that has a strong oxidative activity. MPO has been demonstrated to be a major pathway for O 2 -dependent microbicidal activity. Methods: This study was conducted on 84 neonates. 41 with culture proven sepsis and 43 healthy neonates who served as control. Complete blood count, C-reactive protein quantitative assay and blood gases were done in cases group, MPO enzyme level measured by ELISA was done and compared in both groups. Results: MPO enzyme level was statistically higher in case group compared to control group (P-value < 0.001). There was no statistically significant difference in whether the infected were pre-term or full term. MPO enzyme levels were statistically higher in cases with sepsis without septic shock compared to cases with septic shock (P-value < 0.001). MPO level showed positive correlations with total leukocyte count and absolute neutrophil count. MPO assay (using the cutoff value of 146.5 ng/ml) had a sensitivity of 80% and specificity of 83.9% with a positive predictive value of 92.9%, negative predictive value of 61.5% and accuracy of 82.9%. Conclusion: MPO enzyme level increases significantly in neonates with sepsis. MPO assay is not affected by gestational age but can be affected by deterioration to septic shock. Early diagnosis of sepsis cannot rely on a single laboratory test and clinical decision remains to have the upper hand in diagnosis.