Salivary C-reactive protein and mean platelet volume as possible diagnostic markers for late-onset neonatal pneumonia.

Background: Neonatal sepsis, a formidable threat to newborns, is a leading cause of neonatal mortality, with late-onset sepsis manifesting after 72 hours post-birth being particularly concerning. Pneumonia, a prevalent sepsis presentation, poses a significant risk, especially during the neonatal phase when lung defenses are compromised. Accurate diagnosis of pneumonia is imperative for timely and effective interventions. Saliva, a minimally invasive diagnostic medium, holds great promise for evaluating infections, especially in infants.

Aim: To investigate the potential of serum C-reactive protein (CRP), salivary CRP (sCRP), and mean platelet volume (MPV) as diagnostic markers for late-onset neonatal pneumonia (LONP).

Methods: Eighty full-term neonates were systematically examined, considering anthropometric measurements, clinical manifestations, radiology findings, and essential biomarkers, including serum CRP, sCRP, and MPV.

Results: The study reveals noteworthy distinctions in serum CRP levels, MPV, and the serum CRP/MPV ratio between neonates with LONP and healthy controls. MPV exhibited a robust discriminatory ability [area under the curve (AUC) = 0.87] with high sensitivity and specificity at a cutoff value of > 8.8. Correlations between serum CRP, sCRP, and MPV were also identified. Notably, sCRP demonstrated excellent predictive value for serum CRP levels (AUC = 0.89), underscoring its potential as a diagnostic tool.

Conclusion: This study underscores the diagnostic promise of salivary and serum biomarkers, specifically MPV and CRP, in identifying and predicting LONP among neonates. These findings advocate for further research to validate their clinical utility in larger neonatal cohorts.