Usefulness of ascitic fluid cholesterol as a marker for malignant ascites

The differential diagnosis of ascites is a common clinical problem. However, the capability to distinguish malignant from non-malignant causes of ascites using available biochemical techniques would obviate many expensive and time-consuming diagnostic studies on patients presenting with ascites of unknown etiology. Therefore, this study was planned to evaluate the diagnostic efficacy of ascitic fluid cholesterol in comparison to the efficiency of ascitic/serum total protein, pH, glucose, total leukocyte count, and the serum/ascitic albumin gradient in differentiating "malignant" from non-malignant ascites.

A total of 50 patients (25 with malignant ascites and 25 with non-malignant) were evaluated for total ascitic protein, ascites/serum (A/S) total protein ratio, serum ascites albumin gradient (SAAG), ascitic pH, serum & ascitic cholesterol with glucose.

The mean ascitic cholesterol level was significantly higher in malignant ascites than in non-malignant ascites, with a cut off level of 70 mg/dl for ascitic fluid cholesterol; 22/25 (88%) patients with malignant ascites could be separated from the 25 patients with non-malignant ascites. The specificity (100%) and diagnostic efficiency (94%) of ascitic fluid cholesterol is better than the 84% specificity and 86% diagnostic efficiency of serum ascitic albumin gradient.

Total Ascitic protein (70%), Ascitic serum protein ratio (74%), ascitic leukocyte count (54%), and malignant cytology (82%) yielded much lower diagnostic efficiency than ascitic fluid cholesterol (94%) or SAAG (86%) in the diagnosis of malignant ascites.