Procalcitonin and C-reactive protein in WHO defined severe and very severe community acquired pneumonia: A hospital based cross-sectional study

Objectives To correlate and compare serum levels of procalcitonin (PCT) and C-reactive protein (CRP) in children with severe and very severe community acquired pneumonia (CAP), as defined by World Health Organization (WHO) and also had radiological abnormalities consistent with pneumonia. Methods This was a cross-sectional study, done in a tertiary care teaching hospital in north India. Included were children aged between 2 months and 5 years, hospitalized for CAP. Definitions of WHO for diagnosing severe and very severe pneumonia have been used as gold standard. Written informed consent was obtained from parents. Those, who have wheeze, fever more than 14 days, and severe malnutrition, were excluded. For estimations of serum PCT and CRP levels, commercially available enzymes linked fluorescent assay and enzymes linked immune-sorbent assay kits were used, respectively. Results From June 2013 to September 2013, fifty cases were recruited, among which 56% ( n =28/50) and 44% ( n =22/50) were very severe pneumonia and severe pneumonia, respectively. In cases of very severe pneumonia and severe pneumonia, mean serum PCT levels were 17.65±18.9ng/ml and 0.93±2.91ng/ml ( p =0.01) and mean serum CRP levels were 85.25±17.83mg/dl and 56.50±23.13mg/dl ( p ≤0.01), respectively. Serum PCT and CRP levels were positively linearly correlated ( r =0.45). Using serum PCT levels >2ng/ml and serum CRP levels >60mg/dl, cut-off for differentiating very severe and severe pneumonia, the sensitivity was same (92.9%), but specificity of PCT was higher (86.4%) than CRP (63.6%). Area under receiver operating characteristics (ROC) curves was 0.923 and 0.837 for serum PCT and CRP, respectively. Conclusion Serum PCT and CRP are positively linearly correlating with each other and PCT has better differentiating ability between very severe and severe pneumonia than CRP.