Ascites Albumin Gradient
Info
Serum Albumin
unit g/L g/dL
Ascites Albumin
unit g/L g/dL
R e s u l t s
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SAAG
 
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Ascites Albumin Gradient

Ascites is the abnormal accumulation of fluid inside the peritoneal cavity. This is a common clinical condition that has multiple possible causes; with the most common being chronic liver disease.

 

The serum-ascites albumin gradient (SAAG) helps in determination of the cause of ascites. The SAAG probably discriminates better than older measures for cause of ascites (transudate versus exudate).

 

According to a 1992 study by Runyon, et al. with subsequent validation in smaller trials, SAAG had 97% accuracy and can provide a rational clinical approach to the work-up of ascites.

The serum ascites albumin gradient (SAAG) is calculated by subtracting the albumin concentration of the ascitic fluid from the albumin concentration of a serum specimen obtained on the same day.The formula used is:

SAAG (g/dL) = Serum Albumin - Ascites Albumin

 

Note: Specimen should be obtained on the same day. If numbers do not agree with the clinical scenario, the test should be repeated.

 

Interpretation:

  1. A SAAG >= 1.1 suggests presence of portal hypertension in patients with a transudative ascites.
  2. A SAAG<1.1 suggests absence of significant portal hypertension in patients with exudate ascites.

The classification of types of ascites according to the level of SAAG (97% accuracy was obtained using SAAG = 1.1g/dL as cut-off

>=1.1g/d

  • Cirrhosis
  • Alcoholic hepatitis
  • CHF
  • Massive hepatic metastases
  • Vascular occlusion
  • Fatty liver disease of pregnancy
  • Myxedema

<1.1g/dL

  • Peritoneal carcinomatosis
  • Peritoneal TB
  • Pancreatitis
  • Serositis
  • Nephrotic syndrome
  • Bowel obstruction / infarction / perforation

Reference :

Das B, et al. Comparative utility of sero ascites albumin gradient and ascitic fluid total protein for differential diagnosis of ascites. Indian Pediatr. 1998 Jun;35(6):542-5.Runyon BA, et al. The serum-ascites albumin gradient is superior to the exudate-transudate concept in the differential diagnosis of ascites. Ann Intern Med. 1992 Aug 1;117(3):215-20.