Initial Management of Ascites

Mandatory Initial Testing

The European Association for the Study of the Liver recommends performing a diagnostic paracentesis immediately in all patients with new-onset ascites, and sending the fluid for cell count with differential, total protein, and albumin to calculate the serum-ascites albumin gradient (SAAG) 1, 2
Cell count and differential are essential to detect spontaneous bacterial peritonitis (SBP), which is diagnosed when neutrophils exceed 250 cells/mm³, as recommended by the American Association for the Study of Liver Diseases 3, 1, 2
Ascitic fluid albumin is required to calculate SAAG, which differentiates portal hypertension from other causes with 97% accuracy, according to the European Association for the Study of the Liver 1, 4
Serum albumin must be drawn simultaneously to calculate SAAG accurately, as recommended by the American Association for the Study of Liver Diseases 1, 4
Ascitic fluid total protein identifies patients at high risk for SBP (protein <15 g/L) and helps distinguish cardiac ascites (protein >2.5 g/dL with high SAAG) from cirrhotic ascites, as suggested by the Clinical and Molecular Hepatology journal 3, 1, 6

A SAAG ≥1.1 g/dL indicates portal hypertension with 97% accuracy and predicts response to sodium restriction and diuretics, according to the European Association for the Study of the Liver 1, 4, 5
High SAAG causes include cirrhosis, cardiac ascites, Budd-Chiari syndrome, and sinusoidal obstruction syndrome, as reported by the Clinical and Molecular Hepatology journal 6, 5
Low SAAG causes (<1.1 g/dL) include peritoneal carcinomatosis, tuberculous peritonitis, pancreatic ascites, and nephrotic syndrome, as suggested by the Clinical and Molecular Hepatology journal 3, 5

Cytology should be ordered for suspected malignancy, with a yield varying from 0-96.7% depending on tumor site, as recommended by the American Association for the Study of Liver Diseases 1
Amylase should be ordered for suspected pancreatic ascites, typically >1,000 IU/L or >6 times serum amylase, as suggested by the Clinical and Molecular Hepatology journal 3, 1
Adenosine deaminase should be ordered for suspected tuberculous peritonitis, with levels <40 IU/L excluding TB with high accuracy, as reported by the Clinical and Molecular Hepatology journal 3, 1

Diagnostic paracentesis should be performed urgently in hospitalized cirrhotic patients with any signs of infection, gastrointestinal bleeding, hepatic encephalopathy, worsening renal or liver function, hypotension or shock, or hospital admission, as recommended by the American Association for the Study of Liver Diseases 1, 2

Fluid appearance alone should not be relied upon for diagnosis, as both ascites and urine can appear clear or cloudy, and creatinine level definitively distinguishes them, as suggested by the Praxis Medical Insights journal 7
CA125 should not be used as a diagnostic marker, as it is elevated by ascites from any cause and has no diagnostic value, as reported by the Clinical and Molecular Hepatology journal 3
Mixed ascites should be recognized, as approximately 5% of patients have multiple causes contributing to fluid accumulation, as suggested by the Clinical and Molecular Hepatology journal 3, 6
Culture-negative neutrocytic ascites (PMN >250 cells/mm³ with negative culture) requires the same treatment as culture-positive SBP due to similar morbidity and mortality, as recommended by the American Association for the Study of Liver Diseases 1