Procalcitonin is not an accurate marker of spontaneous bacterial peritonitis in patients with cirrhosis.

BACKGROUND/AIMS: The clinical features of peritonitis are usually absent in cirrhotic patients with an ascitic fluid infection, raising the interest for specific biological markers of inflammation.
METHODOLOGY: We prospectively measured the plasma and ascitic fluid levels of procalcitonin, an innovative infection parameter, interleukin-6, and C-reactive protein in 20 cirrhotics with or without spontaneous bacterial peritonitis. The patient's condition was followed-up for 12 weeks after paracentesis.
RESULTS: None of the 10 patients with spontaneous bacterial peritonitis presented with severe systemic signs of infection. Procalcitonin level in plasma, but not in ascites, was significantly higher in patients with spontaneous bacterial peritonitis compared to controls (0.74 +/- 0.6 vs. 0.2 +/- 0.1 ng/mL, P < 0.05). Interleukin-6 levels in ascites were similar between groups. C-reactive protein concentrations were higher both in plasma and in ascitic fluid in patients with spontaneous bacterial peritonitis compared to controls (85.3 +/- 63 vs. 18.6 +/- 19 mg/dL, 24.6 +/- 25 vs. 4.5 +/- 4 mg/dL, P < 0.05, respectively). Three patients with spontaneous bacterial peritonitis died, but the outcome was not related to the concentrations of biological markers.
CONCLUSIONS: In spontaneous bacterial peritonitis, procalcitonin measurement is not an accurate diagnostic test, possibly due to the absence of systemic inflammatory response syndrome in this condition. In addition, the diagnostic value of C-reactive protein is limited by the wide overlap between values.