Study On The Clinical Application Of Serum Procalcitonin In Patients With Adult Community-acquired Lower Respiratory Tract Infection

Objective: To investigate clinical application value of the serum procalcitonin and the relationship between serum procalcitonin (PCT) and early diagnosis, treatment and condition assessment in patients with adult community-acquired lower respiratory tract infection (LRTI).Methods: 67 patients with community-acquired lower respiratory tract infection (LRTI),20 patients with systemic inflammatory response syndrome (SIRS) and 25 healthy people were enrolled in this study. The concentrations of PCT were measured by enzyme linked-immunosorbent assay (ELISA ) on 1st , 3rd ,7th day after admission.. Acute physiology and chronic health evaluation (APACHE II) was observed in patients with lower respiratory tract infection.Results: The level of PCT in lower respiratory tract infection patients with bacteria was significantly higher than that of in lower respiratory tract infection patients with non-bacterial. The sensitivity and specificity were 71.4% and 66.7% respectively when the threshold value was 0.177ug/l according by receiver-operating- characteristics (ROC) analysis. The level of PCT in bacterial infection group with SIRS was significantly higher than that of non-infectious group with SIRS while the numbers of leukocytes, neutrophils percentage and the level of C-reactive protein were similar. The concentration of serum PCT (ug/l)on the 1st, 3rd, 7th day after admission were 0.30士0.16, 0.19士0.11 and 0.13士0.10 respectively in lower respiratory tract infection patients with bacteria, declined consistent with remission (P <0.05). There was a positive correlation between the concentration of PCT and APACHE II score in patients with infection (r=0.351,P<0.05).Conclusions: The serum PCT concentrations in adult lower respiratory tract bacterial infections were elevated and no change occurred in non-bacterial infection gruop. The level of PCT correlated with the severity of LRTI. PCT concentrations of SIRS with infection increased while they had no significant change in non-infectious SIRS group. Dynamic detection of PCT concentrations shows that it returns to normal with infection control.