The purpose of this study was to provide evidence-based approaches to detect ascites, perform paracentesis, order tests, and interpret the results. A Medline search was performed to identify relevant articles. Of 731 identified articles, 50 articles were used. The most sensitive findings for ascites detection are ankle edema (93%), increased abdominal girth (87%), flank dullness (84%), and bulging flanks (81%). Paracentesis is safe, with bleeding rates and leakage of <1%. An ascitic fluid polymorphonuclear cell count >or=250 cells/mm(3) is the most sensitive test (86%-100%) to diagnose spontaneous bacterial peritonitis. The serum-ascites albumin gradient is the most useful test in identifying portal hypertension-related ascites. Large-volume paracentesis is effective in the treatment of refractory ascites. We conclude that paracentesis is a safe and vital procedure in patients with new-onset ascites. Once detected, an algorithmic approach to ordering tests and their interpretation is useful to determine etiology and direct further management.