Procalcitonin levels in bacterial and viral infections

Objective To explore the value of serum procalcitonin( PCT) in different causes of fever patients. Methods We collected the cases with final diagnosis with bacterial or viral infections from April 2006 to October 2012,whose ages were no less than 16 years,and the PCT level was tested without antibiotics treatment. The serum PCT was determined by Enzyme linked fluorescence analysis ( ELFA) using miniVIDAS. The optimal cut-off values of PCT were established by using receiver operator characteristic curve( ROC curve) . Results 150 cases were retrospectively enrolled in this study,in which there were 46 cases with bacterial infection and 104 cases with virus infection. The ROC analysis showed that the optimal cut-off value was 0. 5750 ng / ml between bacterial infection and viral infection. The area under ROC curve was 0. 844,and the specificity,sensitivity,positive predictive value, negative predictive value and the total accuracy were 67. 4% ,97. 1% ,85. 71% ,87. 07% and 79. 33% ,respectively. For systemic bacteria infection and local bacteria infection,the ROC analysis showed the optimal cut-off value was 2. 1450 ng / ml. The area under ROC curve was 0. 739. The specificity,sensitivity,positive predictive value,negative predictive value and the total accuracy were 76. 9% ,69. 7% ,50% ,88. 46% and 71. 74% ,respectively. Conclusions Serum PCT could serve as a good risk predictor for bacterial infection and systemic bacterial infection. The cut-off value was 0. 5750 and 2. 1450,respectively,which had the highest diagnostic efficiency with specificity and sensitivity. It might be helpful to differential diagnosis of fever.