[The diagnosis of sepsis].

The early diagnosis of sepsis is mandatory for the further reduction of mortality due to sepsis. Current findings exist that accentuate the role of the time factor, comparable with acute myocardial infarction or with ischemic stroke. On the other hand, there are no generally accepted diagnostics for sepsis, realizing the demands of early diagnosis and based on the physician's experience.The diagnostics start with the recognition of the inflammatory reaction caused by infection (at least 2 of 4 criteria of inflammatory reaction have to be fulfilled). This definition has high sensitivity, but remarkably lower specificity and it leads either to too frequent admissions or only to hospitalization in case of a complicating organ failure. Making a careful history and knowledge about sepsis are essential for the out-patient department physicians. In addition to the varying pictures of sepsis, the clinicians have laboratory findings available, most of all procalcitonin. Patients have to be considered as septic with a serum PCT level higher than 1 ng/ml particularly when clinical signs do not exclude sepsis and in cases of positive blood cultures. Initially PCT is a product of macrophages if the defense reaction starts, but it becomes an infection marker, when the serum PCT level declines less than the half life falls.