Ab0163 Peculiarities of Interpretation of the Procalcitonin Test in Rheumatological Patients

Background: Assessment of serum procalcitonin (PCT) levels is of great interest in rheumatology in the diagnosis of infections, including infectious complications during active immunosuppressive therapy. Objectives: To evaluate the significance of PCT as a specific marker of infection in rheumatological patients. Methods: The study included 100 patients with inflammatory rheumatic diseases; PCT in the blood serum was determined for all of them. Results: Infectious diseases were diagnosed in 41 out of 100 patients: 11 had a generalized infection, 30 had a focal infection. In the generalized infection group, PCT was significantly higher than in the local infection group (p=0.004) and the group without infection (including those with highly active rheumatic disease), p<0.0001. There were no significant differences in PCT values in the group with local infection and in the group without infection (including those with highly active rheumatic disease, p = 0.8. C-reactive protein levels and erythrocyte sedimentation rate correlated with PCT concentrations in different groups of patients (Table 1). According to ROC analysis, the optimal values of sensitivity (82%) and specificity (98%) of PCT in the diagnosis of systemic infection in patients with rheumatic diseases corresponded to a PCT concentration of ≥2.3 ng/ml, while the area under the curve (AUC) was 0,9, which indicates the high clinical informativeness of the test. According to the area under the characteristic curve (ROC analysis), when differentiating systemic infection/without infection, the effectiveness of the PCT test is "excellent", when differentiating local infection/without infection – "good", when differentiating systemic infection/local infection – "very good". Conclusion: Determination of PCT contributes to the diagnosis of generalized infections, and also helps in the differential diagnosis of systemic RZ and infectious pathology. The issues of determining diagnostically significant threshold values of PCT deserve further study in the course of prospective comparative studies. REFERENCES: NIL. Acknowledgements: NIL. Disclosure of Interests: None declared.