PCT levels in sepsis are generally higher than 1-2 ng/ml and can reach values between 10 and 100 ng/ml, or considerably higher in individual cases, thus enabling the diagnostic differentiation between various clinical conditions and a severe bacterial infection (sepsis) (Fig. 2).
In healthy people, plasma PCT concentrations are found to be below 0.05 ng/ml, but PCT concentrations can increase up to 1000 ng/ml in patients with sepsis, severe sepsis or septic shock. PCT levels are low in viral infections, chronic inflammatory disorders or autoimmune processes .
These cut-off definitions were made in accordance with the results of the consensus conference of the American College of Chest Physicians/Society of Critical Care Medicine (sepsis-1) and
the SCCM/ESICM/ACCP/ATS/SIS International Sepsis Definitions Conference (sepsis-2) where severe sepsis was still a distinguishing criterion [10,12]. Since 2016, a new sepsis definition
(sepsis-3) came into force. Since according to the new definition every form of sepsis is associated with organ dysfunction, the term “severe sepsis” should no longer be used .