SAAG Calculator 🧪
Calculate Serum-Ascites Albumin Gradient (SAAG) to differentiate portal hypertension from other causes of ascites. Uses Irish/British units (g/L).
🎯 What is SAAG?
- SAAG = Serum Albumin - Ascites Albumin
- Threshold: ≥11 g/L (≥1.1 g/dL) indicates portal hypertension
- High SAAG (≥11 g/L) = Transudative ascites
- Low SAAG (<11 g/L) = Exudative ascites
- Accuracy: ~97% for exudative/transudative classification (more accurate than Light's criteria)
- Units: g/L (Irish/British standard)
📊 Clinical Interpretation
- High SAAG (≥11 g/L): Transudative - Portal hypertension likely
- Low SAAG (<11 g/L): Exudative - Portal hypertension unlikely
- SAAG is more accurate than traditional Light's criteria for classification
- Consider ascites protein if SAAG borderline (10-12 g/L)
- Always correlate with clinical findings and imaging
🔍 High SAAG Causes (Portal Hypertension)
- Cirrhosis (most common cause)
- Heart failure (right-sided)
- Budd-Chiari syndrome
- Portal vein thrombosis
- Constrictive pericarditis
- Veno-occlusive disease
🔍 Low SAAG Causes (Non-Portal Hypertension)
- Peritoneal carcinomatosis
- Tuberculous peritonitis
- Nephrotic syndrome
- Pancreatic ascites
- Chylous ascites
- Serositis (SLE, etc.)
⚠️ Important Notes
- False positive rate: <3%
- False negative rate: ~5%
- Most accurate when ascites protein <25 g/L (<2.5 g/dL)
- Consider other tests if clinical picture unclear
- SAAG remains valid even with diuretic use
- Units: All values in g/L (Irish/British standard)
Links
SAAG Calculator
Serum-Ascites Albumin Gradient
Educational reference only. Medical disclaimer