SAAG Calculator – Serum-Ascites Albumin Gradient

Written by Great Medico

Updated September 24, 2026 •2 min read

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Lab and glucose-related numbers are easier to use when the conversion or equation is transparent. SAAG Calculator – Serum-Ascites Albumin Gradient keeps the calculation focused on the values you enter.

What this calculator does

The serum-ascites albumin gradient, or SAAG, helps clinicians classify ascites by comparing albumin in serum with albumin in ascitic fluid. Metabolic calculations can add context to measurements, but laboratory timing, assay methods, medications, and the clinical situation can change what the result means.

How to use it

Enter or select Serum albumin and Ascites albumin. Use the units offered by the calculator and keep measurements consistent when you plan to compare results over time.

How the calculation works

The equation is SAAG = serum albumin − ascites albumin, using matching concentration units. The calculator compares the result with the commonly used 1.1 g/dL threshold in its interpretation.

Example

For the sample values prefilled in this calculator, the primary result is 2 g/dL (Serum–ascites albumin gradient). This example is there to show how the inputs flow through the implemented equation; replace the sample values with your own measurements before using the result.

How to interpret the result

A SAAG of 1.1 g/dL or higher generally supports portal-hypertension physiology, while a lower gradient suggests looking for non-portal-hypertensive causes. The result should be combined with the rest of the ascitic-fluid analysis and clinical picture.

Limitations and notes

SAAG does not identify the exact cause of ascites by itself. Sample timing, albumin measurement, infection, malignancy, cardiac disease, cirrhosis, and other conditions still require clinical evaluation. The serum and ascites albumin values should ideally be obtained close in time. When laboratory values are involved, use results from the same units and note whether the sample was fasting or taken under other specified conditions. A mathematically correct result can still be clinically misleading when the underlying test or timing is inappropriate.