Biomarkers of Infection: Are They Useful in the ICU?

Abstract

Biomarkers are increasingly used in patients with serious infections in the critical care setting to complement clinical judgment and interpretation of other diagnostic and prognostic tests. The main purposes of such blood markers are (1) to improve infection diagnosis (i.e., differentiation between bacterial vs. viral vs. fungal vs. noninfectious), (2) to help in the early risk stratification and thus provide prognostic information regarding the risk for mortality and other adverse outcomes, and (3) to optimize antibiotic tailoring to individual needs of patients (“antibiotic stewardship”).Especially in critically ill patients, in whom sepsis is a major cause of morbidity and mortality, rapid diagnosis is desirable to start timely and specific treatment.Besides some biomarkers, such as procalcitonin, which is well established and has shown positive effects in regard to utilization of antimicrobials and clinical outcomes, there is a growing number of novel markers from different pathophysiological pathways, where the final proof of an added value to clinical judgment and ultimately clinical benefit to patients is still lacking.Without a doubt, the addition of blood biomarkers to clinical medicine has had a strong impact on the way we care for patients today. Recent trials show that as an adjunct to other clinical and laboratory parameters these markers provide important information about risks for bacterial infection and resolution of infection. Moreover, biomarkers can help to optimize management of patients with serious illness in the intensive care unit, thereby offering more individualized treatment courses with overall improvements in clinical outcomes.

Monocyte Distribution Width (MDW) as a New Tool for the Prediction of Sepsis in Critically Ill Patients: A Preliminary Investigation in an Intensive Care Unit

“…In such patients, it is crucial to establish when empirical antimicrobials should be started, as microbiological assays often require, even under the best established diagnostic work plans, hours to days to provide their results, which may be relevant in unstable patients [31]. In ammatory biomarkers, determined daily throughout the patient's stay, may be potentially useful to pick up early ensuing sepsis in ICU patients [8,32,33]. To date, PCT was documented as the best biochemical marker, with a large base of evidence supporting PCT-guided therapy deescalation and outcome prediction.…”

Complementary use of Presepsin with the Sepsis-3 Criteria Improved Identification of High-Risk Patients with Suspected Sepsis

“…Various circulating biomarkers have shown prognostic value in many studies, but few markers have been used in clinical practice due to the controversial issues in clinical value [3]. Among them, procalcitonin (PCT), lactate, and C-reactive protein (CRP) have been widely used for risk assessments of critically ill septic patients [4]. However, these biomarkers also have limitations, including the nonspeci c nature of sepsis and the fact that no single biomarker is su cient to represent all aspects of sepsis [5].…”

“…Therefore, presepsin is expected to be a promising biomarker that could identify patients with sepsis who are at high risk for poor prognosis more quickly and sensitively. However, there have been con icting results regarding the clinical value of presepsin [4,10] In this study, the primary aim is to evaluate the prognostic accuracy of presepsin in patients with suspected sepsis. We also investigated whether presepsin could be used complementarily with the current sepsis de nition and lactate to identify high-risk patients.…”

Association of kidney function with effectiveness of procalcitonin-guided antibiotic treatment: a patient-level meta-analysis from randomized controlled trials

“…Among different other clinical and laboratory markers, procalcitonin (PCT) has emerged as an adjunct to clinical judgement to assess the risk for bacterial infection and treatment response to antibiotic therapy [2][3][4]. PCT is released by different tissues in the body in response to systemic inflammation caused by bacterial infections through cytokine stimulation (e.g., interleukin [IL)-1β, IL-6 or tumor necrosis factor [TNF]-α) [5][6][7]. The short time until PCT increases after bacterial infection and the kinetic profile, which differs in patients with and without response to infection [8], make PCT an interesting marker to monitor patients with infections and help to early reduce antibiotic treatment in case of a favorable clinical response [9,10].…”