Serum Ascites Albumin Gradient (SAAG)

The SAAG is calculated by subtracting the ascitic fluid albumin level from the serum albumin level. The serum albumin level is measured in the blood, while the ascitic fluid albumin level is determined from a sample of the accumulated fluid in the abdominal cavity.

The SAAG test is done to

• Assess the cause of ascites in the abdomen.
• Diagnose and monitor conditions such as liver disease, cirrhosis, heart failure, tuberculosis, pancreatic diseases, and certain cancers. 
• Differentiate between portal hypertension and non-portal hypertension causes of ascites, allowing for accurate diagnosis and appropriate treatment.

The SAAG test is recommended:

• if you have symptoms of abdominal distention
• pain, or discomfort
• along with other signs of liver disease or cirrhosis.

It is suitable for patients with suspected portal hypertension or ascites due to liver dysfunction or other underlying conditions.

The SAAG value provides an indirect measurement of the pressure within the portal venous system, which is the blood vessel system that supplies the liver. It reflects the gradient of albumin between the blood and the ascitic fluid.

SAAG ≥ 1.1 g/dL: This high gradient indicates portal hypertension-related ascites. The most common cause is cirrhosis of the liver, which leads to increased pressure in the portal vein system. Other causes can include alcoholic liver disease, hepatitis, and certain vascular disorders affecting the liver.

SAAG < 1.1 g/dL: This low gradient suggests non-portal hypertension-related ascites. The fluid accumulation in the abdomen is not primarily due to increased portal pressure. Causes of low-gradient ascites can include malignancy, tuberculosis, pancreatic disease, heart failure, and certain infections.

During the test, a blood sample and ascitic fluid sample are collected. The blood sample is taken from a vein in your arm, while ascitic fluid is obtained by inserting a thin needle into your abdomen. You may experience mild discomfort during the procedure. 

Before SAAG, your doctor may advise you to discontinue certain medications that can affect test results. Follow any instructions given by your doctor regarding eating, drinking, or medication intake prior to the test. Please reach out to your healthcare provider for any specific requirements.

Other tests that may be ordered alongside SAAG include:

• Liver Function Tests: These measure various liver enzymes and proteins to evaluate liver function.
• Abdominal Ultrasound: It uses sound waves to create images of the abdomen, helping identify any abnormalities.
• Ascitic Fluid Analysis: This analyses the composition of ascitic fluid to assist in diagnosing the cause of ascites.

Ascitic Fluid Albumin Gradient, Ascites Albumin Gradient

Portal hypertension refers to increased blood pressure within the portal venous system, which carries blood from the digestive organs to the liver. It is usually caused by liver diseases such as cirrhosis. This condition can lead to complications like ascites and variceal bleeding.