Procalcitonin and C-reactive protein predict infection in hematopoietic stem cell transplantation patients

Procalcitonin (PCT) and C-reactive protein (CRP) are known inflammatory markers of severe infection; however, their ability to differentiate between infections of different origins is not clear yet. In this study, we evaluated PCT and CRP as markers of infection in hematopoietic stem cell transplantation (HSCT) patients.

Blood samples were collected to determine serum concentrations of PCT, CRP, d-Dimer, and to perform blood culture analysis. Based on blood culture results, the patients were divided into two groups-positive blood culture (n = 271) patients and negative blood culture patients (n = 668); the negative blood culture group served as the control. The positive blood culture group was further divided into three groups based on the etiological agent of infection. PCT and CRP concentrations were compared, and ROC curve, sensitivity, specificity, and cutoff values were calculated.

PCT levels in infected patients were significantly higher than those in control patients (p < 0.001); similarly, CRP and d-Dimer levels were also higher among infected patients when compared with those in the controls. A PCT level of 0.51 ng/mL was the best threshold for detecting the infection, with an AUC-ROC of 0.877, whereas the best threshold for CRP was 49.20 mg/L. PCT levels were the highest in patients with gram-negative bacteremia as compared to in those with gram-positive bacteremia and fungal infection. The optimal cutoff value of PCT for the detection of gram-negative and gram-positive infection was 1.63 ng/mL.

PCT seems to be a useful marker for the diagnosis of systemic infection in HSCT patients, probably better than CRP and d-Dimer.