Background: Spontaneous bacterial peritonitis (SBP) is a fatal complication of liver cirrhosis with high mortality rates. The aim of this study is to investigate the diagnostic utility of absolute neutrophil count (ANC) as a non-invasive marker for SBP diagnosis.
Methods: Six hundred patients with cirrhotic ascites were included in the study. All patients underwent abdominal paracentesis and the ascitic fluid was processed for cell count and culture.
Results: Absolute neutrophil count was significantly higher in SBP versus non-SBP and in culture positive SBP versus culture negative SBP. ANC at cutoff value > 2.804 has 84% sensitivity and 78% specificity for diagnosis of SBP with positive and negative predictive values (79.4% and 83.6 respectively). At a cut-off point > 5.6, ANC is capable of differentiating culture positive SBP from culture negative SBP cases with 62.07% sensitivity and 60.87 % specificity. Increased ANC, white blood cell (WBC), C reactive protein (CRP), creatinine and decreased platelet emerged as independent risk factors for SBP development, while increased ANC, WBC and decreased platelets were independent predictors of culture positive SBP. 
Conclusion: This study demonstrates that, ANC count is simple, non-invasive diagnostic marker for SBP. Increased ANC, WBC, CRP, creatinine and decreased platelet emerged as independent risk factors for SBP development.