Background: The most reliable way to diagnose Spontaneous bacterial peritonitis [SBP] is with a positive ascitic fluid culture for a pathogen. However, it is invasive method. Several studies had reported another noninvasive tool for the diagnosis of SBP.
The Aim of the work: the aim of the study is to evaluate the predictive value of PEC index in diagnosis of spontaneous Bacterial Peritonitis, which made by measurement of procalcitonin, ESR and CRP, which we called the PEC index as a predictive value in Decompensated liver disease ascites.
Patients and Methods: This study was carried on 120 patients with cirrhosis.  All patients were selected from Internal Medicine Department at Al-Azhar University Hospital New Damietta. All patients were divided into the following groups: Group [A] include: Forty [40] patients with decompensated cirrhosis having SBP. Group [B] include: Forty [40] patients with decompensated cirrhosis having sterile ascites. Group [c] include: Forty [40] patients with compensated cirrhosis without ascites.
Results: We found that PCT in 0.48ng/mL cutoff level had sensitivity of 86% and specificity of 92%. ESR in 30.5 cutoff level had sensitivity of 84% and specificity of 64.4%. CRP in 23.5 cutoff level had sensitivity of 88% and specificity of 75.6%. PEC in 25 cutoff level had sensitivity of 92% and specificity of 97.8%.
Conclusion: The PEC index is effective in diagnosis of spontaneous Bacterial Peritonitis, which made by measurement of procalcitonin, ESR and CRP, which we called the PEC index as a predictive value in Decompensated liver disease ascites.