Etiology of ascites and the diagnostic value of serum-ascites albumin gradient in non-alcohol liver disease.

This study was designed to determine the different etiologies of ascites and the diagnostic value of serumascites albumin gradient (SAAG) in patients with ascites of non-alcoholic liver disease in Southern Saudi Arabia. A total of 132 patients with ascites (96 males and 36 females, mean age 58.8+/-15.9 years) were studied for the different causes of ascites. In 55 patients with liver disease and 22 patients with nonliver disease (malignancy and peritoneal tuberculosis), we compared SAAG with the three usual parameters of ascitic fluid biochemical analysis used in the differential diagnoses of ascites. The nonliver disease group showed higher ascitic fluid total protein (aTP) concentration (4.77+/-2.05 versus 1.98+/-1.56 g/dL), ascitic to serum ratio of total protein (a/sTP) concentration (0.75+/-0.43 versus 0.26+/-0.19), ascitic fluid lactic dehydrogenase (aLDH) level (565.4+/-353.4 versus 254.1+/-205.03 U/L) and a lower SAAG (0.6+/-0.30 versus 1.71+/-0.61). P7lt;0.0001 for all parameters. The positive predictive values for aTP, a/sTP, aLDH and SAAG to detect ascites due to liver disease were 68%, 76%, 67%, and 80%, respectively, while the negative predictive values were 96%, 96%, 84%, and 98%, respectively. Liver causes accounted for 69.7% of cases, followed by peritoneal tuberculosis 10.6%, malignancy 9.1%, congestive heart failure 7.6%, and nephrotic syndrome 3.0%. SAAG is a useful diagnostic parameter which can be used to separate ascites of liver disease (nonalcoholic) from other causes of ascites, with an efficiency of 91%. SAAG should replace the traditional parameters (aTP, a/sTP, and aLDH) used in the differential diagnosis of ascites. In our series, liver disease is the major cause of ascites, followed by peritoneal tuberculosis.