Early Diagnosis of Neonatal Sepsis Using the Leukocyte Alkaline Phosphatase Score: A Cohort Study

Abstract

Introduction: The clinical features of sepsis in neonates are subtle and non specific, requiring a high index of suspicion for early diagnosis. Blood culture is the gold standard for diagnosis, but it is time consuming. Therefore, there is a need for a costeffective and reliable screening tool. The Leukocyte Alkaline Phosphatase (LAP) activity of neutrophils is known to increase during bacterial infections in adults. Aim: To determine the activity of LAP in Neonatal Sepsis (NS) and compare the results with blood culture. Materials and Methods: This is a prospective cohort study conducted from January 2018 to June 2019 at Mandya Institute of Medical Sciences, Karnataka, India. Total of 200 neonates by their haematological profile were clinically suspected of having sepsis. A peripheral smear was prepared from a drop of blood and stained to assess the LAP activity. In each smear, a total of 100 consecutive segmented neutrophils were examined and were rated from 0 to 4 according to the red granular precipitate intensity within their cytoplasm. The possible range of 0-400. The blood culture report was obtained from the case sheet. The neonates were divided into two groups: Group 1 consisted of culture-proven sepsis cases, and Group 2 consisted of neonates with clinical suspicion of sepsis but negative blood culture results. Descriptive analysis was performed using mean and standard deviation for quantitative variables, and frequency and proportion for categorical variables. Chi-square test was conducted, and a p-value <0.05 was considered statistically significant. Results: Out of the 200 cases studied, 64 neonates showed a positive blood culture. The most common causative organism observed was Klebsiella pneumoniae, which was seen in 56 neonates. The age of the neonates ranged from newborn to 28 days old, with 115 being male. Furthermore, 116 neonates were term neonates, and 146 presented with early onset sepsis. The study revealed a wide range of LAP activity in both groups. In the culture-positive sepsis group, the LAP activity ranged from 36 to 350, while in the clinical sepsis group, it ranged from 10 to 354. Due to the broad range of LAP scores observed, it is concluded that LAP activity is not useful as a screening test. Conclusion: Findings of the present study indicate that LAP activity exhibited a wide range in both the culture-proven and clinical sepsis groups. However, due to this variability, LAP activity does not appear to be a reliable screening test for NS. While LAP activity assessment may still hold diagnostic value, further research is needed to refine its utility and explore its clinical relevance.

Keywords

• blood culture
• clinical sepsis
• culture proven sepsis
• newborn bacterial infections