Can clear ascitic fluid appearance rule out spontaneous bacterial peritonitis?

Objective: The objective of the study was to determine the sensitivity and specificity of abnormal ascitic fluid appearance in the detection of spontaneous bacterial peritonitis (SBP), as a sensitivity approaching 100% could exclude SBP if the fluid is clear. Methods: We performed a retrospective review of all ascitic fluid samples sent for cell count over a 4-year period. Spontaneous bacterial peritonitis was defined as an absolute neutrophil count of more than 250 cells/mm(3) or a positive culture. Abnormal fluid appearance was defined as hazy, cloudy, or bloody. Results: There were 916 ascitic fluid samples analyzed during the study period. Eighteen percent of samples had a clear appearance, whereas 82% were abnormal. Abnormal ascitic fluid appearance had a sensitivity of 98.1% (95% confidence interval, 95.3%-99.5%) and a specificity of 22.7% (95% confidence interval, 19.4%-26.3%) in the detection of SBR. Conclusions: Abnormal fluid appearance has a high sensitivity for the detection of SBR Thus, clear fluid might safely exclude SBP. (C) 2007 Elsevier Inc. All rights reserved.