Serum Procalcitonin Measurement For Detection Of Infection In Febrile Patients With Systemic Lupus Erythematosus (SLE)

Objective: To evaluate the clinical usefulness of serum procalcitonin (PCT) in febrile patients with systemic lupus erythematosus (SLE) to distinguish infection from disease activation. Method: We prospectively enrolled 54 patients with fever who were admitted to Sichuan provincial people' s Hospital between June 2005 and August 2006. Twenty patients with inactive SLE were enrolled as controls. At the detection of fever, the clinical inflammatory markers and PCT were performed. These markers are considered positive if PCT≥0.5ng/ml and CRP≥8mg/L We compared the value of PCT and CRP in predicting infection. Result: The patients were divided into groups on the basis of viral infection, non-viral infection, and non-infection. Serum PCT tended to be significantly higher in group with non-viral infection(mean(SD,1.10(0.98)ng/ml) than in the group with viral infection(mean(SD,0.30(0.16)ng/ml ,p=0.025),the group with non-infection (mean(SD, 0.13 (0.13)ng/ml, p=0.005),and the controls(mean(SD, 0.11(0.07) ng/ml, p=0.004). There was no statistical difference in the PCT levers of the groups with viral infection or non-infection and the control group. PCT has the higher specificity(93.3%), positive predictive(88.9%),negative predictive (73.7%)in contrast to CRP. The area under the ROC curve that used procaltcitonin to predict infection was0.935(95%CI 0.874to 0.996).In comparison, the area under the ROC curve for CRP was 0.798 (95%CI 0.693 to 0.963). PCT are more reliable indicators to differentiate bacterial infection than CRP (u = 2.20, P = 0.0139) .Conclusion: Detection PCT is useful to distinguish bacterial infection from disease activation in febrile patients with SLE.