Serum Ascites Albumin Gradient (SAAG)

Serum Albumin :
Ascites Albumin :

SAAG is the standard for defining presence of portal hypertension (does not differentiate cause) in patients with ascites.

Formula :

SAAG = (albumin concentration of serum) – (albumin concentration of ascitic fluid).

Explanation of Result :

A high gradient (> 1.1 g/dL) indicates the ascites is due to portal hypertension with 97% accuracy.

About the Calculation :

* Please verify all calculations prior to clinical use.


  • Hoefs JC. The mechanism of ascitic fluid protein concentration increase during diuresis in patients with chronic liver disease. Am J Gastroenterol. 1981 Nov;76(5):423-31. PMID: 7337129.

  • Paré P, Talbot J, Hoefs JC. Serum-ascites albumin concentration gradient: a physiologic approach to the differential diagnosis of ascites. Gastroenterology. 1983 Aug;85(2):240-4. PMID: 6862152.