What is a normal SAAG value?

There is no universally "normal" SAAG — the clinical cutoff is 1.1 g/dL. Values at or above 1.1 g/dL indicate portal hypertension; values below 1.1 g/dL suggest non-portal causes. The gradient is only meaningful in the context of confirmed ascites.

Why is SAAG preferred over the older exudate/transudate classification?

The SAAG has a diagnostic accuracy of approximately 97% for portal hypertension, compared to about 56% for the older Light's criteria applied to ascitic fluid. SAAG directly reflects the oncotic-hydrostatic pressure balance across the hepatic sinusoids.

What conditions cause a high SAAG (≥ 1.1 g/dL)?

Common causes include liver cirrhosis, alcoholic hepatitis, cardiac ascites (congestive heart failure, constrictive pericarditis), Budd-Chiari syndrome, portal vein thrombosis, and massive liver metastases.

What conditions cause a low SAAG (< 1.1 g/dL)?

Low SAAG causes include peritoneal carcinomatosis, peritoneal tuberculosis, pancreatitis, nephrotic syndrome, serositis from connective tissue disorders, and bowel obstruction or infarction.

When should SAAG not be used alone?

SAAG should be interpreted alongside clinical findings, ascitic fluid cell count, culture, LDH, glucose, and cytology. Patients with two simultaneous causes of ascites (e.g., cirrhosis plus peritoneal carcinomatosis) may have intermediate values that are misleading.

Must both samples be collected at the same time?

Yes. Serum and ascitic fluid albumin should ideally be collected within the same 24-hour period (simultaneously is best) to ensure the gradient accurately reflects the current hemodynamic state.

Ascites SAAG Calculator

Name: Ascites SAAG Calculator
Availability: InStock
Author: Nham Vu

Enter serum and ascitic fluid albumin levels to calculate the SAAG and classify the cause of ascites.

Lab Values

Enter albumin concentrations from the same collection period.

Serum Albumin (g/dL)

Normal range: 3.5 – 5.0 g/dL

Ascitic Fluid Albumin (g/dL)

Obtained from diagnostic paracentesis

Formula

SAAG = Serum Albumin − Ascitic Albumin

Cutoff: ≥ 1.1 g/dL = portal hypertension

Enter lab values and click Calculate

Clinical Note: SAAG is a screening tool only. Always correlate with history, physical examination, and additional ascitic fluid analysis (cell count, culture, LDH, glucose, cytology).

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Summary

Enter serum and ascitic fluid albumin levels to calculate the SAAG and classify the cause of ascites.

How it works

Enter the serum albumin concentration measured from a blood sample (g/dL).
Enter the ascitic fluid albumin concentration from paracentesis analysis (g/dL).
The calculator subtracts the ascitic albumin from the serum albumin to produce the SAAG.
A SAAG ≥ 1.1 g/dL indicates portal hypertension with 97% accuracy.
A SAAG < 1.1 g/dL suggests a non-portal cause of ascites.
Review the differential diagnosis list provided for each result category.

Use cases

Differentiate cirrhotic ascites from malignant or infectious ascites.
Guide clinical workup for new-onset ascites in hospitalized patients.
Support decision-making before initiating diuretic therapy.
Confirm portal hypertension in patients with chronic liver disease.
Evaluate ascites etiology when multiple causes are suspected.
Assist medical students and residents in bedside clinical reasoning.

Frequently Asked Questions

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Last updated: 2026-05-23 · Reviewed by Nham Vu