The predictive and diagnostic values of procalcitonin and C-reactive protein for clinical outcome in febrile neutropenic patients.

BACKGROUND Procalcitonin (PCT) represents a new marker of systemic inflammatory reactions to bacterial infections. The main aim in this study was to determine the diagnostic value of PCT in predicting the clinical severity of febril neutropenic attacks, compare it with that of C-reactive protein (CRP), and clarify its importance in culture-positive attacks. METHODS Between February 2001 and April 2002, 36 patients who were neutropenic due to various hematologic disorders and febrile were entered into the study. Blood samples were obtained on the first day of fever for the measurement of serum PCT and CRP levels. RESULTS In clinically severe neutropenic fever attacks, means of serum PCT and CRP levels were measured as 0.93+/-1.33 ng/mL and 67+/-24 mg/L, while they were 0.37+/-0.23 ng/mL and 32+/-19 mg/L in clinically mild ones (p = 0.033 and p < 0.001). On the other hand, no statistical significance was found between culture-positive and negative attacks when either serum PCT or CRP levels were taken into consideration (p = 0.133 and p = 0.141). The specificity and positive predictive value of the serum PCT test for severe febrile neutropenia was higher than that of the serum CRP test (0.80 vs. 0.57 and 0.50 vs. 0.39). However, sensitivity and negative predictive value for CRP were higher than the values for PCT (1.00 vs. 0.40 and 1.00 vs. 0.73). Diagnostic value and positive likelihood ratio of CRP for severe febrile neutropenia were higher than those of PCT (71 vs. 67 and 2.32 vs. 2.00). CONCLUSIONS PCT and CRP are comparable with each other in prediction of the clinical severity of febrile neutropenic attacks. Furthermore, serum CRP levels correlate with the duration of fever.