Objective      To investigate the diagnostic criteria for spontaneous bacterial peritonitis (SBP) in patients with chronic liver failure.     Methods      A total of 1 003 inpatients with chronic liver failure in our department during 2008.01 to 2011.05 were enrolled. Retrospective data from clinical records of 385 consecutive episodes of SBP were chosen. One hundred twenty-six patients with ascitic fluid polymorphonuclear leucocyte (PMN) counts ≥250×10

6

/L we

re assigned to group A; One hundred and five patients with ascitic fluid white blood cell (WBC) counts ≥250×10

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/L and PMN counts ＜250×10

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/L were assigned to group B; Fifty-six patients with ascitic fluid WBC counts ＜250×10

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/L and proportion of PMN in ascitic fluid≥50% were assigned to group C; the remaining 98 patients were assigned to group D. WBC or PMN counts in ascitic fluid before and after antibiotic treatment

and the prognosis of patients in the four groups were analyzed.     Results      After antibiotic treatment for 7 d

patients with ascitic fluid PMN counts less than 250×10

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/L accounted for 71.4% (20/28) in group A; the ascitic fluid WBC counts of group B was significantly lower than those before treatment (P0.05)

but the ascitic fluid WBC counts of group C and group D were not significantly different from those before treatment (P0.05).     Conclusions      Ascitic fluid WBC count≥250×10

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/L is a more reasonable criterion and is important for diagnosis of SBP. It is recommended to extend the course of antibiotic treatment (more than 7 d) for SBP in patients with chronic liver failure．