Procalcitonin and C-reactive protein in early diagnosis of sepsis caused by either Gram-negative or Gram-positive bacteria

Background Sepsis is the most frequent cause of systemic inflammatory response syndrome (SIRS). Procalcitonin (PCT) and C-reactive protein (CRP) are well-known predictors of sepsis. Serum PCT levels are associated with blood culture positivity in patients with sepsis, but the magnitude of elevation of PCT and CRP levels at the onset of sepsis is unknown in Gram-negative (GN) bacteremia and in Gram-positive (GP) bacteremia. Aims To evaluate the PCT and CRP levels in 72 h at the onset of sepsis in GN and GP bacteremia. Methods We retrospectively analyzed the data from 648 blood-positive specimens from three integrated teaching hospitals in Xiamen, China. One hundred and forty-seven adult patients with sepsis within 72 h enrolled in the study. Serum PCT and CRP level were assessed according GN or GP bacteremia. Results A total of 147 (22.68 %) patients were eligible for inclusion in the study, including 56 GP sepsis and 91 GN sepsis. PCT, but not CRP levels, was significantly higher in patients in the GP group than in the GN group (23.64 vs 6.18 ng/mL, p < 0.001). The area under the receiver-operating characteristic (ROC) curve of PCT was 0.73 (95 % confidence interval 0.65-0.81) and that under the ROC curve of CRP was 0.52 (95 % confidence interval 0.43-0.62). A positive predictive value of 72.5 % and a negative predictive value of 67.9 % were achieved with a PCT cutoff value of 2.1 ng/ml. Conclusion Serum PCT levels are higher in GN sepsis than GP sepsis in 72 h. There are not differences in CRP. The separation of PCT and CRP phenomenon is helpful for early diagnosis of GP sepsis.