Relationship Between Procalcitonin and Other Inflammatory Biomarkers in Critical Ill Patients in the Intensive Care Unit: A Retrospective Study

Objective: Procalcitonin, white blood cell count, neutrophil count, C-reactive protein and mean plate volume are biomarkers that are frequently used in clinics and whose levels increase in infective and inflammatory processes. We aimed to investigate the relationship between procalcitonin and other biomarkers based on normal and abnormal procalcitonin values in critically ill patients admitted to the intensive care units. Material and Methods: A total of 9.867 records of 1.357 patients admitted to different intensive care units were included in the study. Firstly, the correlation between procalcitonin values and other biomarkers was evaluated. Then, a cut-off value for , white blood cell count, neutrophil count, C-reactive protein and mean platelet volume was determined based on normal and abnormal procalcitonin values using ROC analysis. Results: The correlation between procalcitonin and the other inflammatory markers was statistically significant (p˂0.001) for the relationship between all biomarker values and procalcitonin level. A weak positive correlation was found only between the procalcitonin and C-reactive protein level (r=0.272). There was either no correlation between other biomarker values and the procalcitonin level. The results of ROC analysis showed that sensitivity was very low (1-1.3%), although AUC > 0.5, p<0.001, specificity 99.9% and LR + values were high in all tests. Conclusion: Abnormal and normal procalcitonin levels were primarily correlated with C-reactive protein levels in critically ill patients admitted to intensive care units and that identifying a suitable cutoff value for white blood cell count, C-reactive protein, neutrophil count, and mean platelet volume based on abnormal and normal procalcitonin levels would not be useful due to low sensitivity values.