Objective: Various inflammatory molecules that are used for diagnosis and monitoring are released into circulation when a bacterial infection is observed at host organisms. C reactive protein (CRP) is one of these various molecules, and procalcitonin (PCT) is also an acute phase protein that is identified as a marker of bacterial infection recently. This study compares PCT to CRP in order to determine the usefulness of measuring PCT levels in intensive care unit and inpatient-outpatient clinics.

Materials and Methods: The data of simultaneous PCT and CRP levels of the patients who applied to our laboratory between January 2008 and March 2011 were examined for this study. 3449 patients were used in total, 2090 of them being from intensive care unit and 1395 of them being from inpatient-outpatient clinics. Additionally, SpearmanÕs correlation test was applied between CRP and PCT measurements because of the possible non-regular distribution of the values. Non-parametric Mann-Whitney U test was also used to determine the differences between the groups.

Results: Results: It was found that there is a significant correlation between CRP and PCT levels in all patients (r = 0.653, p < 0.001). However, the results of the comparison between the samples from intensive care unit and inpatient-outpatient clinics for CRP and PCT levels were also statistically significant (p < 0.001).

Conclusion: Thus, PCT is recently used for monitoring the patients with bacterial infection, and it is correlated with CRP. Besides because PCT analysis has a higher cost, CRP may be preferred in the evaluation of patient monitoring in bacterial infections.