Day to Day Change in Procalcitonin (PCT) and Lactate to Predict Sepsis and Hospital Mortality

Abstract

PURPOSE: PCT increases in response to severe systemic bacterial infections and sepsis early after ICU admission, however, the value of a day to day change is less understood. We studied the predictive value of PCT in comparison to lactate and absolute neutrophil count (ANC) for the diagnosis of sepsis and hospital mortality in patients admitted to a MICU. METHODS: Consecutive patients admitted for ≥12 hrs. were included in this prospective observational study. Measurements of serum PCT were obtained on admission and then daily during the MICU stay. Lactate and ANC were measured as part of the routine clinical practice. SIRS, Sepsis, Severe Sepsis, and Septic Shock were defined according to standard criteria and assessed daily. Diagnostic and predictive accuracy was assessed by the area under the receiver operating characteristic curve (AUC). RESULTS: 318 patients were enrolled in the study. Mean ± SD APACHE IV score was 69.8 ± 30. 44% were septic on ICU admission and 7 % became septic later on. The AUC and cut-offs for PCT and lactate as predictors of sepsis on admission were 0.76 (1.46 ng/mL) and 0.62 (1.0 mmol/L), respectively. The AUC for maximal PCT and lactate as sepsis predictors at any time during the ICU stay were 0.80 and 0.68 with cut-offs values similar to the admission ones. The combination of PCT + lactate did not increase the AUC (0.70 and 0.79 for admission and max any time, respectively). ANC was not better than the flip of a coin to predict sepsis development. Lactate had an AUC of 0.72 and 0.76 and PCT 0.64 and 0.66 for mortality prediction based on values on admission and at any time thereafter, respectively. CONCLUSIONS: PCT has a superior diagnostic accuracy for sepsis that was not improved by the addition of lactate to the predictive model. PCT is less helpful to predict ICU mortality.