Serum Procalcitonin for Differentiating Bacterial Infection from Disease Flares in Patients with Autoimmune Diseases.
10.3346/jkms.2011.26.9.1147
- Author:
Kowoon JOO
1
;
Won PARK
;
Mie Jin LIM
;
Seong Ryul KWON
;
Jiyeol YOON
Author Information
1. Division of Rheumatology, Department of Internal Medicine, Inha University Hospital, Incheon, Korea. parkwon@inha.ac.kr
- Publication Type:Original Article ; Research Support, Non-U.S. Gov't
- Keywords:
Procalcitonin;
Autoimmune Diseases;
C-reactive Protein;
Bacterial Infections
- MeSH:
Adult;
Aged;
Area Under Curve;
Autoimmune Diseases/complications/*diagnosis;
Bacterial Infections/complications/*diagnosis;
C-Reactive Protein/analysis;
Calcitonin/*blood;
Female;
Humans;
Male;
Middle Aged;
Odds Ratio;
Protein Precursors/*blood;
ROC Curve;
Retrospective Studies;
Sensitivity and Specificity
- From:Journal of Korean Medical Science
2011;26(9):1147-1151
- CountryRepublic of Korea
- Language:English
-
Abstract:
Early differentiation between bacterial infections and disease flares in autoimmune disease patients is important due to different treatments. Seventy-nine autoimmune disease patients with symptoms suggestive of infections or disease flares were collected by retrospective chart review. The patients were later classified into two groups, disease flare and infection. C-reactive protein (CRP) and serum procalcitonin (PCT) levels were measured. The CRP and PCT levels were higher in the infection group than the disease flare group (CRP,11.96 mg/dL +/- 9.60 vs 6.42 mg/dL +/- 7.01, P = 0.003; PCT, 2.44 ng/mL +/- 6.55 vs 0.09 ng/mL +/- 0.09, P < 0.001). The area under the ROC curve (AUC; 95% confidence interval) for CRP and PCT was 0.70 (0.58-0.82) and 0.84 (0.75-0.93), which showed a significant difference (P < 0.05). The predicted AUC for the CRP and PCT levels combined was 0.83, which was not significantly different compared to the PCT level alone (P = 0.80). The best cut-off value for CRP was 7.18 mg/dL, with a sensitivity of 71.9% and a specificity of 68.1%. The best cut-off value for PCT was 0.09 ng/mL, with a sensitivity of 81.3% and a specificity of 78.7%. The PCT level had better sensitivity and specificity compared to the CRP level in distinguishing between bacterial infections and disease flares in autoimmune disease patients. The CRP level has no additive value when combined with the PCT level when differentiating bacterial infections from disease flares.
