Salivary C-Reactive Protein and Mean Platelet Volume in the Diagnosis and Follow-Up of Community-Acquired Pneumonia in Infants.

Community-acquired pneumonia (CAP) in infants is a major cause of morbidity and mortality, especially in developing countries. Increased salivary C-reactive protein (CRP) levels have been demonstrated in neonatal pneumonia and other diseases. We investigated the applicability of CRP and mean platelet volume (MPV) in the diagnosis and follow-up of CAP in infants. This prospective observational study included 45 infants admitted for CAP. We measured serum and salivary CRP levels via ELISA, while MPV was measured using an automated blood cell counter. Both salivary and serum CRP values were significantly different in the studied population between admission and follow-up ( = 0.001 and  < 0.0001, respectively). The same was observed for MPV ( < 0.0001). We found significant positive correlations between serum and salivary CRP ( = 0.652,  < 0.0001) and between serum CRP and MPV ( = 0.495,  = 0.001), as well as between salivary CRP and MPV ( = 0.439,  = 0.003). Receiver operating curve analysis showed that salivary CRP at a cutoff value of 3.2 ng/L had a sensitivity of 97.2% and specificity of 90%, while MPV at a cutoff value of 8.4 fL showed 91% sensitivity and 90% specificity. The present study showed that both salivary CRP and MPV are reliable diagnostic markers of CAP in infants.