Calculators · Gastroenterology & Hepatology · Formula

Serum-ascites albumin gradient (SAAG)

Also called SAAG, albumin gradient

Separates portal-hypertensive from non-portal-hypertensive ascites.

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Formula and scoring

SAAG = serum albumin − ascitic albumin (samples drawn the same day). Threshold 1.1 g/dL (11 g/L).

Exam and ward pearls

  • SAAG replaced the exudate/transudate concept: 96.7% vs 55.6% correct classification (Runyon 1992).
  • High SAAG with ascitic protein > 2.5 g/dL supports a cardiac source (AASLD 2021).

When not to rely on it

  • Serum and ascitic samples must be drawn at the same time.

Source

  1. 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):215-20. doi:10.7326/0003-4819-117-3-215 · PMID 1616215
  2. Biggins SW, Angeli P, Garcia-Tsao G, et al. Diagnosis, evaluation, and management of ascites, spontaneous bacterial peritonitis and hepatorenal syndrome: 2021 practice guidance by the AASLD. Hepatology. 2021;74(2):1014-1048. doi:10.1002/hep.31884 · PMID 33942342

Formula and cut-offs checked against these sources on 8 Nov 2026. Educational tool for clinicians; it does not replace clinical judgement.

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