Abstract: Objective To compare the utility of serum-ascites albumin gradient(SAAG) with the exudate-transudate concept in the classification of ascite.Methods One hundred and twenty three patients with ascites were enrolled into our study.Serum and ascitic fluid were obtained on the same day.SAAG,ascitic fluid total protein(AFTP),ascites/serum total protein ratio(A/S) and ascitic fluid LDH were measured.SAAG was defined as the serum albumin concentration minus the ascitic fluid albumin concentration,and it was classified into high-gradient(SAAG≥11 g/L) and low-gradient(SAAG<11 g/L).AFTP≥25 g/L,(A/S)≥0.5,LDH≥200 U/L were diagnosised as exudates fluid.Results The mean SAAG in patients with diseases associated with portal hypertension was significantly higher than that in patients with diseases not associated with portal hypertension[(19.32±4.39)g/L vs(7.11±2.73) g/L,P<0.01],giving a significantly higher diagnostic sensitivity,specificity and accuracy(95.69%,90.00% and 94.31%,respectively) than that of exudate-transudate classification(62.60%,67.48% and 75.61%,respectively).Conclusion SAAG is valuable to differentiate ascitic fluid of portal hypertension from that of non-portal hypertension,and is superior to the exudate–transudate classification.

Key words: serum-ascites albumin gradient, portal hypertension, ascites