Procalcitonin in a semi-quantitative test and C-reactive protein in the evaluation of postoperative patients admitted to a critical care unit

Introduction

Procalcitonin and C-reactive protein (CRP) are acute phase proteins produced by stimulation to infectious and inflammatory factors, and are greatly used because they present more clinical applicability with practicality and fast detection. The objective of this study is to evaluate which of these markers shows better capacity to predict the evolution of postoperative patients during their stay in the ICU.

Materials and methods

An observational study, performed between February and March 2004 in an ICU of a tertiary hospital. Postoperative patients with more than 24 hours of stay in the ICU and older than 18 years were included in the sample. A semi-quantitative test of procalcitonin (BRAHMS Laboratory) was performed after the patient enrollment.

Results

Twenty-six patients were included, 31% submitted to urgent surgery and 69% to elective surgery. The mean age was 71.5 ± 10.6 years and 53% were female. The mean APACHE II score and SOFA score were 19.2 ± 4.9 and 5.8 ± 2.5, respectively. Every patient presented two or more criteria for systemic inflammatory response syndrome, and the rate of ICU mortality was 30.8%. Among the survivors none presented a procalcitonin test ≥ 2 ng/ml, against 57.1% of non-survivors (P = 0.02). The mean value of CRP was 13.0 ± 6.2 between survivors and was 15.4 ± 7.3 among non-survivors (P = 0.34). The predictive capacity of these variables, as evaluated by the area under the ROC curve, was 0.835 for procalcitonin and 0.634 for CRP.

Conclusion

The semi-quantitative test of procalcitonin was superior to the CRP dosage as a predictor of worse evaluation in this population. This information would be of utility if provided early at the bedside in the identification of patients with potentially unfavorable outcome.