Biomarkers in sepsis-looking for the Holy Grail or chasing a mirage!

Table 1 Biomarkers in sepsis

Biomarker	Description
Procalcitonin	Precursor of hormone calcitonin secreted by C cells of thyroid gland
C-reactive protein	Acute phase protein secreted by hepatocytes in response to pathogen or tissue damage
IL6	A cytokine, mainly produced by macrophages and lymphocytes in response to infection and it can affect the activation of B and T lymphocytes
suPAR	A protein derived from cleavage and release of cell membrane bound urokinase plasminogen activator receptor
sTREM1	Mainly expressed on the surface of polymorphonuclear cells and mature monocytes
Presepsin (sCD14-ST)	sCD14 is cleaved by proteases during inflammation, to form an N terminal fragment-the sCD14 subtype (sCD14-ST)
Adrenomedullin	A 52 amino acid peptide initially isolated from phaeochromocytomas. It is secreted by mammalian tissues and endothelial cells in response to various stimuli such as hypoxia, angiotensin 2, inflammatory cytokine such as TNF-α, IL-1β, etc.
Mid regional Proadrenomedullin (MR-proADM)	A peptide secreted by multiple tissues in order to stabilize the microcirculation and protect against endothelial permeability

IL: Interleukin; sTREM1: Soluble triggering receptor expressed on myeloid cells 1; suPAR: Soluble urokinase plasminogen activator receptor; TNF: Tumor necrosis factor.