Serum ascites albumin gradient

The serum–ascites albumin gradient (SAAG) is the difference between the concurrently obtained serum albumin concentration and the albumin concentration of the ascitic fluid obtained during paracentesis.

Pathology

A difference ≥1.1 grams/deciliter (g/dL) indicates portal hypertension as the likely etiology, whereas a gradient which is <1.1 g/dL implies an etiology that causes increased vascular permeability in the portal system.

Differential diagnosis

A (partial) differential diagnosis of potential etiology, based on the SAAG, is as follows :

• serum-ascites albumin gradient ≥​1.1 g/dL
  • ascites due to portal hypertension
    • cirrhosis
    • cardiac cirrhosis
    • alcoholic hepatitis
    • Budd-Chiari syndrome
• serum-ascites albumin gradient <1.1 g/dL
  • ascites not due to portal hypertension
    • tuberculous ascites
    • pancreatic ascites
    • biliary ascites
    • peritoneal carcinomatosis