At present, over 250 biomarkers for sepsis have been studied, as well as their performance in comparison with current CRP, PCT, and lactate laboratory tests. However, most research has indicated these biomarkers perform no better than the currently utilized PCT test and are more comparable to CRP.
However, one research route is toward pro-inflammatory cytokines, which mediate the initial response of the immune system to injury or infection. Those cytokines attract circulating polymorphonuclear leukocytes (PMNs) to the site, entering circulation, and may also be potentially useful as biomarkers of sepsis.
Interleukin-6 (IL-6), a glycoprotein produced by macrophages, is one such example finding use outside of the US.
(IL-6 is being used in Europe and Asia as an early biomarker of infection, cancer, and sepsis.)