超声检查可检出300ml 以上的腹水,并能鉴别为包裹性抑或游离性腹水。以往关于腹水性质的鉴别,是从腹水的外观,比重、蛋白及白细胞计数等方面进行分析。一般认为腹水蛋白<2.5或3g%的是漏出液,常见于肝硬化腹水;腹水蛋白>2.5或3g%的是渗出液,常见于肿瘤、腹膜结核、原发性细菌性腹膜炎(SBP)和肾功能衰竭腹水等。但肝硬化腹水蛋白>2.5或3g%者占12～17%,此外,Budd-Chian 氏综合征及心源性肝充血腹水的 Ultrasound can detect more than 300ml of ascites, and can be identified as wrapped or ascites. In the past on the nature of ascites identification, ascites from the appearance, weight, protein and white blood cell count and other aspects of analysis. Generally believed that ascites <2.5 or 3g% of the leakage of fluid, common in cirrhotic ascites; ascites protein> 2.5 or 3g% of the exudate, common in cancer, peritoneal tuberculosis, primary bacterial peritonitis (SBP) and Ascites and other renal failure. However, cirrhosis of the ascites protein> 2.5 or 3g% of 12 to 17%, in addition, Budd-Chian’s syndrome and cardiac cirrhosis ascites