Diagnosis value of serum procalcitonin and C-reactive protein in community-acquired pneumonia

Objective To explore the diagnosis value of serum procalcitonin(PCT) and C-reactive protein(CRP) in community-acquired pneumonia(CAP). Methods A total of 122 patients diagnosed as lung disease which of 54 patients with CAP and 68 patients with non-bacterial infection of lung disease were enrolled. According to the severe pneumonia diagnosis criteria,the bacterial infection group was divided into severe pneumonia and light and moderate pneumonia. Routine bloods, PCT, CRP,etiology and other relevant indicators were recorded and compared. ROC curve were described and analyzed. Results The PCT and CRP in patients with CAP were significantly higher than those in patients with non-bacterial infection(t=3.62, 7.25,P0.05). The PCT and CRP in severe groups were significantly higher than those in the light and moderate groups(t=2.37,2.65,P0.05). ROC curve analysis showed that the areas of PCT and CRP under the ROC curve in all patients were 0.89 and 0.88 respectively. The best diagnostic threshold of PCT and CRP were 0.09 μg/L and29.27mg/L respectively. The areas of PCT and CRP under the ROC curve in patients with CAP were 0.80 and 0.74 respectively. The best diagnostic threshold of PCT and CRP were 0.17 μg/L and 85.17mg/L respectively. At this point, the sensitivity of PCT and CRP were 88.89% and 66.67%, the specificity were 66.65% and 80.55%. PCT had high sensitivity to the severe bacterial infection. For severe bacterial infection, PCT had higher sensitivity than CRP while its specificity had no obvious difference. Conclusions PCT and CRP in patients with CAP were higher than those in patients with non-bacterial infection of pulmonary disease. Combined PCT with CRP has a higher specificity in diagnosis of bacterial pneumonia and severe bacterial infection, which is helpful to improve the accuracy of diagnosis.