Which Biomarkers Can Be Used as Diagnostic Tools for Infection in Suspected Sepsis?

Abstract

The diagnosis of infection in patients with suspected sepsis is frequently difficult to achieve with a reasonable degree of certainty. Currently, the diagnosis of infection still relies on a combination of systemic manifestations, manifestations of organ dysfunction, and microbiological documentation. In addition, the microbiologic confirmation of infection is obtained only after 2 to 3 days of empiric antibiotic therapy. These criteria are far from perfect being at least in part responsible for the overuse and misuse of antibiotics, in the community and in hospital, and probably the main drive for antibiotic resistance. Biomarkers have been studied and used in several clinical settings as surrogate markers of infection to improve their diagnostic accuracy as well as in the assessment of response to antibiotics and in antibiotic stewardship programs. The aim of this review is to provide a clear overview of the current evidence of usefulness of biomarkers in several clinical scenarios, namely, to diagnose infection to prescribe antibiotics, to exclude infection to withhold antibiotics, and to identify the causative pathogen to target antimicrobial treatment. In recent years, new evidence with “old” biomarkers, like C-reactive protein and procalcitonin, as well as new biomarkers and molecular tests, as breathomics or bacterial DNA identification by polymerase chain reaction, increased markedly in different areas adding useful information for clinical decision making at the bedside when adequately used. The recent evidence shows that the information given by biomarkers can support the suspicion of infection and pathogen identification but also, and not less important, can exclude its diagnosis. Although the ideal biomarker has not yet been found, there are various promising biomarkers that represent true evolutions in the diagnosis of infection in patients with suspected sepsis.

Negative predictive value of procalcitonin to rule out bacterial respiratory co-infection in critical covid-19 patients

“…There is recent data that suggests that the combination of PCT and CRP levels showed greater accuracy to predict bacterial co-infection in children with influenza H1N1 [42] . Furthermore, not only CRP and PCT levels need to be investigated in additional studies but also some new biomarkers such as inflammatory mediators in the bronchoalveolar lavage fluid, the detection of bacterial genetic code by molecular amplification techniques by polymerase chain reaction and omics which could provide promising results and useful information for clinical decision making in the diagnoses of bacterial co-infection among patients with suspected sepsis [43] .…”

Choosing antibiotic therapy for severe community-acquired pneumonia

“…The simplified ATS criteria (improvement in cough and dyspnoea, absence of fever (>37.8 °C) for more than 8 h, normalization of total leukocyte count by 10% from the previous day, and adequate oral intake) can also be applied [7 ▪▪ ]. Key biomarkers such as a CRP and PCT reduction more than 50% could also be used as a marker for response to further inform the combination algorithm [47]. Patients with sCAP not presenting clinical improvement, that is with the persistence of clinical manifestations or progression of pneumonia with further deterioration are classified as nonresponders.…”

Pancreatic Stone Protein: Review of a New Biomarker in Sepsis

“…The lack of a gold standard test to diagnose infection as well as the overly sensitive and nonspecific features of signs and symptoms of sepsis led medical societies to endorse the use of biomarkers ("inflammatory variables") as surrogate markers of infections to help clinicians in its diagnosis [8]. However, in clinical practice, the diagnosis of infection still relies on the intersection of three vectors: systemic manifestations, organ dysfunction and microbiological documentation [9], and no single biomarker or diagnostic test, per se, has been validated to diagnose infection.…”