SAAG (Serum-Ascites Albumin Gradient)
Calculate the serum-ascites albumin gradient (SAAG) by subtracting the ascitic-fluid albumin from a serum albumin drawn on the same day.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Serum albumin
- 3.5 g/dL
- Ascites albumin
- 1.5 g/dL
Result: SAAG 2.0 g/dL - portal hypertension.
The tool opens with these values already filled in. Replace them with your own.
What the result means
- >=1.1
- High gradient: indicates portal hypertension.
- <1.1
- Low gradient: indicates a non-portal-hypertensive cause.
What you enter
- Serum albumin
- Ascites albumin
What this is
A SAAG >=1.1 g/dL indicates portal hypertension (cirrhosis, heart failure, Budd-Chiari, massive hepatic metastasis, alcoholic hepatitis, or fulminant hepatic failure); a SAAG <1.1 g/dL points to non-portal causes (peritoneal carcinomatosis, tuberculous peritonitis, pancreatic or biliary ascites, nephrotic syndrome, or serositis). Sophie Well returns the gradient to one decimal and labels the portal-hypertensive band. Source: Runyon BA, Montano AA, Akriviadis EA, et al. Ann Intern Med. 1992;117(3):215-220.
When to use it
Use this on the initial diagnostic paracentesis for new-onset ascites, and on any subsequent paracentesis where the etiology is uncertain or the clinical picture is changing. The SAAG has effectively replaced the older transudate/exudate framework for ascitic fluid because it discriminates portal hypertension from non-portal causes with about 97% accuracy. Pair the gradient with the absolute ascitic protein (>=2.5 g/dL with high SAAG suggests cardiac ascites; low total protein with high SAAG suggests cirrhosis and predicts spontaneous bacterial peritonitis risk) and the cell count and differential before settling on a single etiology.
How this is calculated
Runyon BA, Montano AA, Akriviadis EA, et al. The serum-ascites albumin gradient is superior to the exudate-transudate concept in the differential diagnosis of ascites. Ann Intern Med. 1992;117(3):215-220. Read the source ↗
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.
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