SAAG Calculator

The Serum-Ascites Albumin Gradient (SAAG) is calculated by subtracting the ascitic fluid albumin from the serum albumin. It helps clinicians determine whether ascites is caused by portal hypertension or a non-portal-hypertensive condition, guiding appropriate diagnosis and management. See also our Ranson's Criteria.

SAAG = Serum Albumin − Ascitic Fluid Albumin. Both values are measured in g/dL. The serum and ascitic fluid samples should ideally be collected on the same day for the most accurate result.

A SAAG of 1.1 g/dL or greater strongly suggests portal hypertension as the cause of ascites (97% accuracy). Common conditions include cirrhosis, alcoholic hepatitis, cardiac ascites, Budd-Chiari syndrome, and portal vein thrombosis.

A SAAG below 1.1 g/dL indicates a non-portal-hypertensive cause. This includes conditions such as peritoneal carcinomatosis, tuberculous peritonitis, nephrotic syndrome, pancreatic ascites, and bowel obstruction or infarction. You might also find our Fiber Intake Calculator useful.

Yes. The SAAG has largely replaced the older exudate/transudate classification for ascites because it has a higher diagnostic accuracy (~97%) for identifying portal hypertension and better correlates with the underlying pathophysiology.

A falsely high SAAG can occur if the patient has received large amounts of intravenous albumin or if the serum sample and paracentesis are collected at very different times. Chylous ascites may also interfere with albumin measurement.

Yes. Mixed ascites can occur, for example in a cirrhotic patient who also develops peritoneal tuberculosis or malignancy. In such cases the SAAG may still be ≥1.1 g/dL due to the dominant portal hypertensive component, but clinical context and additional testing are essential.

Ideally yes — collecting both samples simultaneously (or within the same clinical encounter) gives the most accurate gradient. Significant time differences, changes in diet, or recent albumin infusion can affect the result.