New–onset ascites: a simplified diagnostic algorithm

Normally, around 2 mL of fluid is present in the peritoneal cavity. Ascites is defined as a pathological (excess) fluid accumulation within the peritoneal cavity.1 The commonest cause of new–onset ascites is liver cirrhosis (cirrhotic ascites) which is responsible for 85% of cases.2 The remaining 15% of cases occur due to causes other than cirrhosis (non–cirrhotic ascites). While malignancy, heart failure, and renal causes predominate in Western countries, malignancy and tuberculosis predominate in developing countries.2,3 Proper management of patients with new–onset ascites depends primarily on determining its cause which relies principally on proper analysis of ascitic fluid.4 To simplify the approach to diagnosis of ascites etiology, this review suggests a two–step approach: Step [I]: Serum ascites albumin gradient (SAAG) plus total protein concentration. Step [II]: Choice of further tests will depend on the results of step [I] including, but are not limited to, cell count with differential, cholesterol, cytology, adenosine deaminase (ADA), and triglyceride.