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The Serum-Ascites Albumin Gradient (SAAG) is a simple subtraction — serum albumin minus ascitic fluid albumin — used alongside a widely published cutoff to classify likely causes of ascites: a gradient of 1.1 g/dL or more suggests portal-hypertension-related causes, while a lower gradient suggests other causes. This calculator is for general reference and educational purposes only — it is not a medical diagnosis. Consult a doctor for actual clinical interpretation.
How it works
Enter serum albumin and ascitic fluid albumin (both g/dL). The tool subtracts the two and classifies the result against the published 1.1 g/dL cutoff.
- Enter serum albumin (g/dL).
- Enter ascitic fluid albumin (g/dL).
- Click Calculate to see your results.
Examples
Serum albumin 3.5, ascites albumin 1.2 (g/dL)
SAAG = 3.5 - 1.2 = 2.3 g/dL — high gradient, suggesting portal-hypertension-related causes.
Who should use it
- Reviewing paracentesis results alongside a doctor.
- Clinical and nursing education about ascites evaluation.
Industry applications
- Gastroenterology and hepatology reference
- Clinical education
Advantages
- Simple arithmetic from two lab values.
- Backed by decades of published clinical research as superior to the older exudate-transudate concept.
Limitations
- A single data point — not sufficient alone to determine the cause of ascites.
- Requires a paracentesis (fluid sampling) to obtain the ascitic fluid albumin value.
Common mistakes to avoid
- Using serum and ascitic fluid albumin values drawn at very different times, which can reduce accuracy.
- Treating the SAAG result as a standalone diagnosis rather than one input to a broader clinical evaluation.
Best practices
- Use albumin values drawn on the same day (ideally the same paracentesis visit) for the most meaningful gradient.
Tips
- Discuss the full clinical picture, not just SAAG, with your doctor when evaluating the cause of ascites.