Early diagnosis of spontaneous bacterial peritonitis: values of ascitic fluid variables

In a search for clinical and laboratory factors that would aid in early diagnosis of spontaneous bacterial peritonitis, we identified two groups of patients with chronic liver disease and ascites: 1) 38 patients with 40 episodes of spontaneous bacterial peritonitis, and 2) 39 randomly selected patients with 40 sterile paracenteses who were matched for severity of liver dysfunction as a reference group. A variety of clinical and laboratory features were examined. The absolute lymphocyte count in peripheral blood was lower for the spontaneous bacterial peritonitis group (mean = 703/mm3 vs. 1,212/mm3, p less than 0.005). Four ascitic fluid variables, i.e., a white blood cell count of greater than or equal to 300/mm3, a polymorphonuclear leukocyte count of greater than or equal to 240/mm3, an ascitic fluid/serum LDH ratio of greater than or equal to 0.4, or an ascitic fluid/serum glucose ratio of less than or equal to 1.0, could separate the spontaneous bacterial peritonitis and reference groups with both sensitivity and specificity of greater than 70%. Although ascitic fluid total leucocyte and polymorphonuclear leucocyte counts are appropriate indicators for the early diagnosis of spontaneous bacterial peritonitis, the possibility of their false positivity should be warranted. The use of multiple tests including ascitic fluid/serum LDH and glucose ratios has better positive predictive value than a single test alone.