Procalcitonin as a marker of severity in septic shock

Procalcitonin (PCT) was shown to be related to the severity of bacterial infection and is recommended as a new parameter of inflammation and infection. To evaluate the prognostic value in septic shock, PCT levels were repeatedly determined and compared with tumour necrosis factor-alpha (TNF-alpha)- and interleukin (IL)-6 bioactivity as well as with C-reactive protein (CRP) serum levels.

Twenty-four surgical patients with septic shock were included. Eight patients died within the study period of 14 days.

Serum levels of TNF-(WEHI 164) and IL-6 (B13-29 subclone 9) bioactivity, CRP and PCT were determined on days 1, 3, 5, 7, 10 and 14 following diagnosis of septic shock.

Survivors and non-survivors were comparable in terms of age and severity of sepsis characterized by the APACHE II score and multiple-organ-failure score. Predominant causes of sepsis were peritonitis and necrotiszing pancreatitis. TNF levels increased in non-survivors with no significant difference to survivors. IL-6 bioactivity was increased on day 1 (P = 0.06) and remained elevated in non-survivors, in whom it was significant on day 7 (P<0.05). CRP was constantly elevated with no difference between the groups. In nonsurvivors PCT remained increased, while the course of survivors was characterized by decreased values which were significantly lower (P<0.05) at every time point compared with those patients who died. A significant correlation could be found on day 1 (P<0.05) and at the end of the observation period (P<0.01) when comparing PCT levels with the multiple-organ-failure score.

PCT seems to be a more reliable prognostic parameter in septic shock than IL-6, while TNF and CRP did not show any difference between survivors and non-survivors. These data indicate that PCT may represent a valuable parameter not only in the diagnosis of sepsis but also in the clinical course of the disease.