SerumAscitesAlbuminGradient

SerumAscitesAlbumin Ratio, often abbreviated as SAA or SAAG, is a laboratory test used to help determine the cause of ascites. Ascites is the accumulation of fluid in the peritoneal cavity, the space between the abdominal wall and the spine. This test measures the difference between the albumin concentration in the serum (blood) and the albumin concentration in the ascitic fluid.

The SAAG is calculated by subtracting the ascitic fluid albumin level from the serum albumin level. A high SAAG, typically defined as 1.1 g/dL or greater, suggests that the ascites is caused by portal hypertension, which is an elevated pressure in the portal vein system. This is most commonly seen in cirrhosis of the liver. Other causes of portal hypertension include alcoholic hepatitis, severe alcoholic hepatitis, Budd-Chiari syndrome, and constrictive pericarditis.

A low SAAG, less than 1.1 g/dL, indicates that portal hypertension is unlikely to be the cause of the ascites. In these cases, other causes such as malignancy (cancer), infection (like tuberculosis peritonitis), pancreatitis, or nephrotic syndrome are more likely.

The SAAG test is a crucial diagnostic tool in the evaluation of ascites, helping clinicians narrow down the potential causes and guide further investigations and treatment. It is a simple, readily available test that provides valuable information for patient management.