The utility of evaluating low serum albumin gradient ascites in patients with cirrhosis

Abstract

Objectives: Serum-ascites albumin gradient (SAAG) has been used extensively in the diagnostic workup of patients with ascites. A SAAG level of <1.1 g/dl is usually thought of as a result of nonportal hypertension etiologies, including malignancies, tuberculous peritonitis, and nephrotic syndrome. However, the predictive value of a low SAAG in patients with existing cirrhosis in whom the pretest probability of portal hypertension is high is not clear.

Methods: We identified all patients with a SAAG of <1.1 g/dl during a 5-year period at a single large veterans affairs medical center. Cirrhosis was defined by clinical, histological, and radiological features. Nonportal hypertension causes of low SAAG were identified, including bacterial peritonitis, peritoneal carcinomatosis, nephrogenous ascites, tuberculous peritonitis, chylous ascites, and pancreatic ascites.

Results: We identified 92 patients (76 with cirrhosis and 16 with no cirrhosis) with ascites and a SAAG of <1.1 g/dl. Of the 76 patients with cirrhosis, only 29 (38%) had an identifiable cause, most commonly primary bacterial peritonitis (11, 38%), followed by peritoneal carcinomatosis or malignant ascites (8, 28%) and nephrotic syndrome (5, 17%). There were 47 patients with cirrhosis and a low SAAG for whom no etiology was identified. Thirty-three patients underwent a repeat paracentesis, 24 (73%) of whom changed to a high SAAG. On the other hand, the 16 patients with no cirrhosis had significantly lower SAAG (0.66 vs. 0.81), and most (12, 75%) had an identifiable cause of ascites.

Conclusions: Evaluation of a SAAG <1.1 g/dl in patients with known cirrhosis has low yield and is less likely to be helpful than that in patients without cirrhosis. A repeat paracentesis as part of the workup is recommended. Further studies of low SAAG cutoffs are needed.