Triggering receptor expressed on myeloid cells-1 is a member of the immunoglobulin superfamily of receptors that is specifically expressed on the surfaces of monocytes and neutrophils.TREM-1 expression is increased in infectious diseases and is associated with the release of soluble TREM-1 (sTREM-1).There has been demonstrated that the value of plasma sTREM-1 levels as an indicator of sepsis was superior, although other studies reported that the value of sTREM-1 for diagnosing sepsis was inferior.An increasing number of studies indicate that there are increased levels of sTREM-1 in body fluid samples for the following diseases and conditions: sepsis, pneumonia, pleural effusion, septic arthritis, meningitis, peritonitis, and uterine cavity infection.