The<unk>  (SAAG) helps determine the cause of<unk> . SAAG = albumin concentration of<unk>  - albumin concentration of ascitic fluid
The SAAG is probably a better discriminant than older measures (transudate versus exudate) for the causes of<unk> . A high<unk>  (> 1.1 g/dL) indicates the<unk>  is due to portal hypertension. A low<unk>  (< 1.1 g/dL) indicates<unk>  of non-portal hypertensive etiology.
Important causes of high SAAG<unk>   (> 11 gm/L) include cirrhosis of the liver, Budd Chiari syndrome and heart failure.
Serum-ascites albumin gradient
Urinary casts
BUN-to-creatinine ratio
Microalbuminuria
Mannheim's Peritoneal index score 
Analgesic nephropathy x-ray
Hematuria x ray
Blood urea nitrogen