SAAG is the standard for defining presence of portal hypertension (does not differentiate cause) in patients with ascites.
SAAG = (albumin concentration of serum) – (albumin concentration of ascitic fluid).
Explanation of Result :
A high gradient (> 1.1 g/dL) indicates the ascites is due to portal hypertension with 97% accuracy.
About the Calculation :
* Please verify all calculations prior to clinical use.
References
- Hoefs JC. The mechanism of ascitic fluid protein concentration increase during diuresis in patients with chronic liver disease. Am J Gastroenterol. 1981 Nov;76(5):423-31. PMID: 7337129.
The mechanism of increase in the protein concentration of ascitic fluid during diuresis was investigated in 27 patients with chronic liver disease. The albumin concentration increased in ascites from .58 +/- .49 gm.% in the initial paracentesis to 1.48 +/- .69 gm.% in the final paracentesis (P less than .001) as the serum albumin concentration increased from 2.40 +/- .44 gm.% 2.94 +/- .56 gm.% (P less than .001). The serum to ascites albumin concentration gradient decreased significantly from 1.82 +/- .39 gm.%-1.46 +/- .45 gm.% (P less than .001). Despite this decrease, the serum to ascites albumin concentration gradient was relatively constant (decrease of .36 gm.% or 20% of initial value) compared to either the absolute or percentage chan […]
- Paré P, Talbot J, Hoefs JC. Serum-ascites albumin concentration gradient: a physiologic approach to the differential diagnosis of ascites. Gastroenterology. 1983 Aug;85(2):240-4. PMID: 6862152.
Serum-ascites albumin concentration gradient, a parameter of oncotic pressure gradient reflecting presence or absence of portal hypertension, was compared with the usual parameters of ascitic fluid analysis in the differential diagnosis of ascites. Twenty-nine patients with liver disease and 15 patients with malignant neoplasm were prospectively studied. The group with malignant neoplasm showed higher ascitic fluid total protein level (3.70 +/- 1.28 vs. 1.66 +/- 1.20 g/dl), ascites to serum ratio of total protein level (0.58 +/- 0.14 vs. 0.26 +/- 0.14), ascitic fluid lactic dehydrogenase level (756 +/- 693 vs. 151 +/- 125 U/L), ascites to serum ratio of lactic dehydrogenase level (1.13 +/- 0.79 vs. 0.35 +/- 0.22), and lower serum-ascites al […]