Application of combined detection of sputum and serum procalcitonin in infants with community acquired pneumonia

Abstract

Objective To evaluate the effects of combined detection of sputum and serum procalcitonin (PCT) to identify the etiology of community acquired pneumonia(CAP) in infants. Methods Retrospective analysis from August 2010 to September 2012 enrolled 435 patients with definitely etiological diagnosis of CAP.The all cases were divided into three groups according to the etiological diagnosis: 243 cases of bacterial infection group(including mixed bacterial infection), 106 cases of viral infection group, and 86 cases of mycoplasma infection group.Sputum and serum PCT levels in all cases were detected, with simultaneous detection of blood leukocytes, C-reactive protein levels. Results Sputum PCT level of bacterial infection group [(8.44±1.08) ng/ml] was significantly higher than viral infection group [(0.32±0.12) ng/ml] and mycoplasma infection group[(0.24±0.17) ng/ml], which showed statistically significant difference(F=765.03, P 0.05). The levels of blood leukocytes and C-reactive protein among 3 groups showed no statistically significant difference(P>0.05). As the critical value of the PCT>0.5ng/ml, the positive rates of sputum and serum PCT were significant difference in bacterial infection group (86.83% vs 73.66%, χ2=13.92, P<0.05). The sensitivity of diagnosing bacterial CAP by sputum and serum PCT levels were 86.83% and 73.66%, the specificity were 86.98% and 88.54%, respectively.The sensitivity and specificity of combined detection sputum and serum PCT were 72.02% and 94.27%. Conclusion Combined detection of sputum and serum PCT has clinical value and efficiency in pathogen identification of CAP. Key words: Procalcitonin; Community acquired pneumonia; Infants