Interleukin 6 (IL-6) is a sensitive indicator for diagnosis of early stage acute infection. It is widely applied in infectious diseases, tumors, arthritis, physical trauma, cardiovascular diseases, renal diseases etc.

The normal concentration of IL-6 in the human body is less than 7pg/mL, and the corresponding relationship between the content of IL-6 and the diagnosis of inflammatory diseases is as follows:

• IL -6 concentration<7pg/mL: Normal
• IL-6 concentration 7-150pg/mL: Presence of mild inflammation or infection;
• IL-6 concentration 150-250pg/mL: General bacterial infection or systemic inflammatory response
• IL-6 concentration >250pg/mL: Suspected sepsis

IL-6 is a polypeptide substance secreted by monocytes, macrophages, T cells, B cells and other cells. It is a kind of cytokine with multiple biological activities such as promoting differentiation and growth of cells. It does not only act on the immune system itself, but also widely act on neural, endocrine, cardiovascular and other systems. IL-6 is also an important cytokine involved in various adjustments of the body. IL-6 plays a core role in regulating the inflammatory immune response and is an important mediator. At early stages of infectious inflammation, monocytes and macrophages produce acute IL-6 while stimulated by Toll-like receptors, and the content of IL-6 in the body increases. Such acute IL-6 will strongly induce the expression of acutephasereactants (APR) such as C-reactive Protein, Serum amyloid A, etc. and reduce the expression of albumin, transferrin, etc. to act its regulatory effects.