Diagnostic value of C- reactive protein and haematological parameters in neonatal sepsis.

Objective: To analyse various parameters of sepsis screen singly and in combination to formulate a guideline for the diagnosis of neonatal sepsis.
Design: A cross-sectional analytical study.
Place and Duration of Study: The neonatal intensive care unit at the Paediatric Department, Military Hospital, Rawalpindi, over a period of seven months from 1st June to 31st December 2003.
Subjects and Methods: One hundred neonates having clinical features of sepsis and 100 normal asymptomatic neonates were evaluated with a set of investigations. C-reactive protein (CRP), erythrocyte sedimentation rate, total leukocyte count, absolute neutrophil count (ANC), immature neutrophils to total neutrophil count ratio (I/T ratio), thrombocytopenia, degenerative changes in the neutrophils and gastric aspirate cytology (GAC) for polymorphs were used for diagnosis of neonatal sepsis.
Results: CRP was positive in 24/28 (85.7%) of group-A (proven sepsis) and 58/72 (80.5%) of group-B (probable sepsis) and had a specificity of 95%. ANC was the second most sensitive test having sensitivity of 71.4 % for group-A and 63.9 % for group-B and 88% specificity. For group-A, sensitivity of GAC for polymorphs and platelet count was 71.4% and 64.3% respectively. The sensitivity, specificity and predictive values (PV) of the individual tests and different tests combination was also calculated for group-A and B.
Conclusion: A set of investigations including CRP, TLC, ANC, thrombocytopenia, cytoplasmic vacuolization in the neutrophils and GAC for polymorphs are highly sensitive in detection of culture negative cases of neonatal sepsis. Moreover, a combination of three tests enhances the sensitivity of these tests.