To evaluate the clinical significance of serum procalcitonin (PCT) in acute infectious diseases. MethodsNinetyeight emergency patients with fever were studied prospectively, then blood samples were taken to test PCT, Creactive protein (CRP) and blood routine. Etiology or serum immunological tests were performed for diagnosis, the value of all test results for diagnosis of bacterial infection were compared. ResultsWhite blood cell, neutrophil ratio, PCT, and CRP in bacterial infection group were all higher than those of nonbacterial infection group (P<0.01). The sensitivity and specificity of PCT was 91.30% and 82.76% respectively, and it had a higher diagnostic value than the other indicators in fever patients with bacterial infection.ConclusionPCT tests are helpful to identify bacterial infection in patients with fever, it has good sensitivity and specificity.