Interrelationships Between Serum Levels of Procalcitonin and Inflammatory Markers in Patients Who Visited a General Medicine Department

Various laboratory markers of inflammation are utilized in general practice, but their clinical diagnostic significance is often ambiguous. In the present study, we determined the clinical significance of the examination of serum levels of procalcitonin (PCT) by comparing the PCT levels with the levels of other inflammatory markers, based on a retrospective review of 332 PCT-positive patients, including cases of bacterial infection (20.5%), non-specific inflammation (20.8%), neoplasm (9.9%), connective tissue diseases (8.4%), and non-bacterial infection (7.2%), were analyzed. The serum PCT level was highest in the bacterial infection group (1.94 ng/ml) followed by the non-specific inflammatory group (0.58 ng/ml) and neoplastic diseases group (0.34 ng/ml). The serum PCT level was positively correlated with serum levels of C-reactive protein (rho=0.62), soluble interleukin-2 receptor (sIL-2R; rho=0.69), and ferritin, the plasma level of D-dimer, and white blood cell count, and negatively correlated with the serum albumin level (rho=−0.52), hemoglobin concentration, and platelet count. The serum PCT level showed a stronger positive correlation with the serum sIL-2R level than the other biomarkers. The results suggest that an increased PCT level may indicate not only an infectious state but also a non-bacterial inflammatory condition in the diagnostic process in general practice.