Diagnostic Accuracy of Procalcitonin for Predicting Blood Culture Results in Patients With Suspected Bloodstream Infection

Abstract

Previous studies have suggested that procalcitonin is a reliable marker for predicting bacteremia. However, these studies have had relatively small sample sizes or focused on a single clinical entity. The primary endpoint of this study was to investigate the diagnostic accuracy of procalcitonin for predicting or excluding clinically relevant pathogen categories in patients with suspected bloodstream infections. The secondary endpoint was to look for organisms significantly associated with internationally validated procalcitonin intervals. We performed a cross-sectional study that included 35,343 consecutive patients who underwent concomitant procalcitonin assays and blood cultures for suspected bloodstream infections. Biochemical and microbiological data were systematically collected in an electronic database and extracted for purposes of this study. Depending on blood culture results, patients were classified into 1 of the 5 following groups: negative blood culture, Gram-positive bacteremia, Gram-negative bacteremia, fungi, and potential contaminants found in blood cultures (PCBCs). The highest procalcitonin concentration was observed in patients with blood cultures growing Gram-negative bacteria (median 2.2 ng/mL [IQR 0.6–12.2]), and the lowest procalcitonin concentration was observed in patients with negative blood cultures (median 0.3 ng/mL [IQR 0.1–1.1]). With optimal thresholds ranging from ≤0.4 to ≤0.75 ng/mL, procalcitonin had a high diagnostic accuracy for excluding all pathogen categories with the following negative predictive values: Gram-negative bacteria (98.9%) (including enterobacteria [99.2%], nonfermenting Gram-negative bacilli [99.7%], and anaerobic bacteria [99.9%]), Gram-positive bacteria (98.4%), and fungi (99.6%). A procalcitonin concentration ≥10 ng/mL was associated with a high risk of Gram-negative (odds ratio 5.98; 95% CI, 5.20–6.88) or Gram-positive (odds ratio 3.64; 95% CI, 3.11–4.26) bacteremia but dramatically reduced the risk of PCBCs or fungemia. In this large real-life setting experience with more than 35,000 patients, procalcitonin was highly effective at excluding bloodstream infections regardless of pathogen categories. The results from our study are limited by its cross-sectional design and deserve to be validated in prospective longitudinal studies.

Diagnostic accuracy of presepsin (sCD14-ST) and procalcitonin for prediction of bacteraemia and bacterial DNAaemia in patients with suspected sepsis

“…Nevertheless, the results of this study are in line with those of a large observational study on 35 343 consecutive patients, in which PCT was highly effective excluding bloodstream infections regardless of pathogen categories, with the highest PCT concentration observed in patients with BCs growing Gram-negative bacteria (Oussalah et al, 2015). Likewise, in a recent systematic review and meta-analysis on 16 514 patients, an AUC of 0.79 was found for PCT in predicting bacteraemia (Hoeboer et al, 2015).…”

Procalcitonin: A promising tool or just another overhyped test?

“…Several studies have supported the use of PCT for making a diagnosis of sepsis [11,[19][20][21][22], while others have recommended its use to rule out sepsis. [23] It has a good negative predictive value for bacterial infection [24], especially bacteremia [25][26][27][28][29], although the current evidence does not suggest a suitable threshold to exclude bacteremia. PCT is detectable in the serum within a few hours after its induction, reaches its peak within 24 hours, and if treatment is adequate, the levels start to decline by approximately 50% per day.…”

Procalcitonina como predictor temprano de bacteriemia en pacientes neutropénicos críticamente enfermos

“…El VPN para gérmenes grampositivos se ha reportado en un 98.4% con niveles de PCT entre 0.4 y 0.75 ng/nl 9,10 . En ausencia de infecciones bacterianas el nivel de PCT es muy bajo (< 0.1 ng/ml) 10 ; en el contexto de un paciente febril, los valores bajos deben conducir a investigar diagnósticos diferenciales que incluyan infecciones virales y causas de fiebre no infecciosa 14 .…”

“…El VPN de la PCT para bacteriemia ha sido reportado como un resultado importante 14 ; por ejemplo, niveles entre 0.4 y 0.75 ng/ml tienen un VPN del 98.4% para bacterias grampositivas y del 99.9% para anaerobios 17 .…”

“…Las causas de altos niveles de PCT sin infección incluyen: politrauma, cirugía mayor, choque cardiogénico y la presencia de metástasis o carcinoma con un componente neuroendocrino, que deben considerarse como limitaciones de este biomarcador 14,18 .…”