Definitions for the terms “SIRS”, “sepsis”, “severe sepsis” or “septic shock” have been proposed by the ACCP/SCCM consensus conference in 1992, and are now widely used (see table
below 1).¹

Clinical need for earlier detection of sepsis
Early detection and specific clinical intervention has been shown to be crucial for the improved outcome of patients with sepsis.  However, sepsis can be difficult to distinguish from other, non-infections conditions in critically ill patients with clinical signs of acute inflammation and negative microbiological results.  Therefore, in the early phase of the disease process it may be difficult to decide on the appropriate therapeutic measures for the individual patient.

Additional specific information may be helpful to increase the accuracy of sepsis diagnosis at an early stage.  A parameter which fulfills these demands to a high degree is procalcitonin.

Fast and highly specific PCT increase in bacterial infection and sepsis
One major advantage of PCT compared to other parameters is its early and highly specific increase in response to severe systemic bacterial infections and sepsis.^2,3  Therefore, in septic conditions, increased PCT levels can be observed 3-6 hours after an infectious challenge.

PCT levels are usually low in viral infections, chronic inflammatory disorders or autoimmune processes.  PCT levels in sepsis are generally greater than 0.5-2 ng/mL and often reach values between 10 and 100 ng/mL, or considerably higher in individual cases, thereby enabling diagnostic differentiation between these various clinical conditions and a severe bacterial infection (sepsis) (Figure 1).

1.  Bone RC, Balk RA, Cerra FB, Dellinger RP, Fein AM, Knaus WA, Schein RM, Sibbald WJ. Definitions for sepsis and organ failure and guidelines for the use of innovative therapies in sepsis. The ACCP/SCCM Consensus Conference Committee. American College of Chest Physicians/Society of Critical Care Medicine. Chest 1992; 101: 1644-55.

2.  Harbarth S, Holeckova K, Froidevaux C, Pittet D, Ricou B, Grau GE, Vadas L, Pugin J; Geneva Sepsis Network. Diagnostic value of procalcitonin, interleukin-6, and interleukin-8 in critically ill patients admitted with suspected sepsis. Am J Respir Crit Care Med. 2001; 164: 396-402.

3.  Muller B, Becker KL, Schachinger H, Rickenbacher PR, Huber PR, Zimmerli W, Ritz R. Crit Care Med. 2000; 28: 977-83. Calcitonin precursors are reliable markers of sepsis in a medical intensive care unit.