Platelet parameters as a diagnostic marker in early diagnosis of neonatal sepsis- Seeking newer answers for older problems

Background: Early identification and intervention of neonatal sepsis can improve the clinical outcome. Blood cultures remain the gold standard for diagnosis but are not easily available and require time. There is a need to identify and validate newer easily available cost-effective investigations, which would help in the diagnosis of neonatal sepsis. Aim: To test the hypothesis that whether platelet parameters, i.e.. total platelet count (TPC), mean platelet volume (MPV), and the ratio of MPV/TPC can serve as diagnostic markers in neonatal sepsis. Methods: It is was a prospective study conducted in a tertiary care neonatal intensive care unit (NICU). The platelet parameters, i.e., TPC, MPV, and MPV/TPC of blood culture-positive septic neonates were compared with those of non-septic neonates admitted to the NICU. The diagnostic accuracy of the platelet indices was assessed by receiver operating characteristics (ROC) curves and sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Result: During the study period, 43 blood culture-positive sepsis neonates were compared with 54 cases of non-septic neonates. There was a significant difference in the mean of TPC, MPV, and MPV/TPC ratio between septic groups and non-septic groups. The sensitivity, specificity, PPV, NPV values of MPV (cut-off >9 fL) were 63.40%, 53.8%, 52.0%. and 65.11% respectively. The sensitivity, specificity, PPV, NPV of MPV/TPC ratio (>7.2) were 48.8%, 96.22%, 90.9%, and 70.42% respectively. The area under the curve (AUC) values for TPC, MPV, and MPV/TPC in the ROC analysis were 0.797, 0.641, and 0.809, respectively. Conclusion: Platelet indices MPV and MPV/TPC ratio can be useful in the early diagnosis of neonatal sepsis.