Clinical relevance of procalcitonin values in bacteremia

The aim of this study was to investigate procalcitonin levels according to the causative pathogens of bacteremia. The relationships between the clinical outcomes and procalcitonin levels were also studied.

From among 452 patients, 507 cases of positive blood culture were included in the present study. Procalcitonin levels were studied according to the pathogen types. The prevalence of septic shock and the mortality rates were also studied in four groups stratified by the procalcitonin levels (groups 1, 2, 3, and 4 had procalcitonin levels of <0.5 ng/mL, 0.5 ≤ 2.0 ng/mL, 2.0 < 10 ng/mL, and ≥10 ng/mL, respectively).

The procalcitonin levels were significantly higher in bacteremia cases with Gram-negative rods (19.50 ng/mL), such as Escherichia coli (32.5 ng/mL), than those with Gram-positive rods (8.45 ng/mL) or Gram-positive cocci (9.21 ng/mL) (p < 0.01). The 28-day mortality rates in groups 1, 2, 3, and 4 were 6.0%, 12.0%, 14.9%, and 19.8%, respectively. The procalcitonin levels of samples taken before or on the same day of blood cultures were significantly lower than those taken one day after blood cultures. Multiple logistic regression analysis showed that C-reactive protein and procalcitonin ≥10 ng/mL were independently associated with a higher risk of mortality within 28 days.

The PCT levels were higher in cases of bacteremia caused by GNR than those caused by GPR or GPC. The 28-day mortality rate increased as the PCT levels increased. Clinical importance of early evaluations and appropriate interpretation of procalcitonin levels for bacteremia were indicated.