1. What is SAAG? The Serum-Ascites Albumin Gradient (SAAG) is a calculation used to determine the cause of ascites, the accumulation of fluid in the peritoneal cavity. The SAAG is calculated by subtracting the albumin concentration in the ascitic fluid from the albumin concentration in the serum (blood).

Formula: $\text{SAAG}=\text{Serum Albumin}-\text{Ascitic Fluid Albumin}$

2. Purpose of the Test: SAAG is primarily used to differentiate between ascites caused by portal hypertension and ascites caused by other conditions.

• High SAAG (≥ 1.1 g/dL): Suggests that the ascites is due to portal hypertension. This can be associated with conditions such as cirrhosis, congestive heart failure, or portal vein thrombosis.

• Low SAAG (< 1.1 g/dL): Suggests that the ascites is due to conditions other than portal hypertension, such as infections (e.g., tuberculosis), malignancy, or nephrotic syndrome.

• High SAAG: Indicates a high risk of complications related to portal hypertension, such as variceal bleeding, hepatic encephalopathy, or spontaneous bacterial peritonitis (SBP). Management often focuses on treating the underlying cause of portal hypertension.

• Low SAAG: Indicates that ascites may be due to other causes, which could require different diagnostic and therapeutic approaches, such as managing infections, treating malignancy, or addressing protein-losing conditions.

• SAAG Normal Range:
  • High SAAG: ≥ 1.1 g/dL (typically considered abnormal and indicative of portal hypertension).
  • Low SAAG: < 1.1 g/dL.

There isn't a "normal" range for SAAG since its purpose is to determine the underlying cause of ascites rather than to assess a specific "normal" value.

• SAAG ≥ 1.1 g/dL:
  • Indication: Portal hypertension (e.g., due to cirrhosis, congestive heart failure, Budd-Chiari syndrome, etc.).
• SAAG < 1.1 g/dL:
  • Indication: Non-portal hypertension causes (e.g., infections, malignancy, nephrotic syndrome).

• Serum Sample: Blood sample is collected to measure the albumin level.

• Ascitic Fluid Sample: Fluid is extracted from the peritoneal cavity via paracentesis to measure the albumin level in the ascitic fluid.