There is much enthusiasm and interest in
sepsis biomarkers, particularly because
sepsis is a highly lethal condition, its diagnosis is challenging, and even simple treatment with
antibiotics has led to serious adverse consequences such as emergence of resistant pathogens. Yet development of a
sepsis biomarker requires many more steps than simply finding an association between a particular molecule and a clinical state or outcome. Demonstration of improvement of therapeutic practice using receiver-operating characteristic and other analyses is important. Validation in independent, prospective and, preferably, multicenter trials is essential. Many promising candidate
sepsis biomarkers have recently been proposed. While
procalcitonin (PCT) is currently the most studied
sepsis biomarker, evidence of potential value has been found for a wide array of blood
biomarkers including
proteins,
mRNA expression in whole blood or leukocytes, micro-RNAs (
miRNA), pathogen and host
DNA, pathogen and host genetic variants and metabolomic panels, and even in the novel use of currently available clinical data. While the most common early reports link putative
sepsis biomarker levels to severity of illness and outcome (prognostic), this is not anticipated to be their primary use. More important is the distinction between
infection and noninfectious inflammatory responses (diagnostic) and the use of
sepsis biomarkers to direct
therapy (predictive).