Serum-Ascites Albumin Gradient (SAAG) Calculator

SAAG is the same-day serum albumin concentration minus the same-day ascitic-fluid albumin concentration after both values are expressed in the same unit.

Sources: [1, 4]

The subtraction is intended to represent one physiologic time point. This page therefore requires both samples to have been collected on the same day; different-day or unknown-timing values are outside its model contract.

Sources: [1, 2, 6]

Yes. Select the unit printed with each result. The calculator independently converts g/L to g/dL before subtraction and never silently reinterprets a number when a unit changes.

Sources: [6, 7]

One g/dL equals 10 g/L. Unit conversion changes only the numeric representation, not the underlying laboratory measurement.

Sources: [6]

Published ascites frameworks historically associate SAAG values at or above 1.1 g/dL (11 g/L) with portal-hypertensive physiology. It is not a certainty, a direct pressure measurement, a disease diagnosis, or a treatment rule.

Sources: [1, 2, 3]

Performance varies by cohort, disease mix, assay, and timing. The 1992 study reported 96.7% overall classification accuracy, but that historical estimate is not a certainty for an individual.

Sources: [1, 3, 7]

No. More than one portal-hypertensive physiologic setting can produce a higher gradient. The result does not identify cirrhosis, cardiac disease, vascular obstruction, or one other cause.

Sources: [2, 3, 5]

No. A lower gradient does not distinguish malignancy, tuberculosis, pancreatic disease, infection, or another non-portal-hypertensive cause by itself.

Sources: [1, 3, 7]

No. SAAG is a concentration difference and not a direct portal-pressure value. It must not be read as a pressure measurement.

Sources: [2, 4, 5]

No. Ascitic total protein is a separate laboratory result and may add context in selected evaluations. It cannot be inferred from serum and ascitic albumin alone.

Sources: [3, 6, 7]

No. Spontaneous bacterial peritonitis assessment uses separate clinical information and ascitic-fluid cell-count and culture testing; SAAG does not replace them.

Sources: [2, 3, 6]

Equal submitted concentrations produce zero. Ascitic albumin above serum albumin produces a negative signed result. The page preserves the arithmetic and prompts review of timing, units, assay, and source reports rather than assigning a cause.

Sources: [1, 6, 7]

They can. Laboratory method, rapidly changing physiology, sample timing, and interventions that affect serum albumin can limit comparison and interpretation even when the arithmetic is correct.

Sources: [3, 6, 7]

The subtraction is mathematical, but the principal evidence and guideline context are adult ascites evaluations. Pediatric ascites and pregnancy require population-specific clinical interpretation beyond this page.

Sources: [2, 3, 7]

No. It does not determine whether or when to perform paracentesis, give albumin or antibiotics, prescribe diuretics, drain fluid, admit a patient, or choose another treatment.

Sources: [2, 3]

Depending on the clinical question, ascitic cell count with differential, culture, total protein, cytology, imaging, liver and renal tests, and other targeted studies provide separate information.

Sources: [2, 3, 6, 7]