SAAG Calculator

Calculate the Serum-Ascites Albumin Gradient (SAAG) by entering your serum albumin and ascitic fluid albumin levels. Get the SAAG value and an interpretation indicating whether ascites is likely caused by portal hypertension (high gradient ≥1.1 g/dL) or non-portal hypertension (low gradient <1.1 g/dL), along with probable diagnoses.

Disclaimer: This tool is for informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making any health-related decisions.

g/dL

Albumin level measured from a peripheral blood sample

g/dL

Albumin level measured from paracentesis fluid sample

Results

SAAG Value

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Gradient Category

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Interpretation

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Probable Causes

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Frequently Asked Questions

What is the SAAG and why is it used?

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.

How is the SAAG calculated?

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.

What does a high SAAG (≥1.1 g/dL) indicate?

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.

What does a low SAAG (<1.1 g/dL) indicate?

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.

Is the SAAG more accurate than the exudate/transudate classification?

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.

What conditions can cause a falsely elevated SAAG?

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.

Can a patient have both portal hypertension and a secondary cause of ascites?

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.

Should the serum and ascitic fluid albumin be collected at the same time?

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.