Ascitic fluid accumulates in the peritoneal cavity due to conditions such as liver cirrhosis, heart failure, infections, or cancers.

Analysis provides critical diagnostic information about the underlying cause.

Clinical uses include:

Differentiating portal hypertension-related ascites (transudate) from infectious or malignant ascites (exudate).

Diagnosing spontaneous bacterial peritonitis (SBP).

Detecting tuberculosis, pancreatitis, or peritoneal carcinomatosis.

Guiding treatment decisions in chronic liver disease and oncology.

The test is performed on fluid obtained via paracentesis.

Physical Examination:

Color, clarity, and appearance of fluid.

Biochemical Tests:

Protein concentration (to classify transudate vs. exudate).

Albumin (used to calculate Serum-Ascites Albumin Gradient, SAAG).

Glucose (low in infection or malignancy).

LDH (elevated in exudates).

Cell Count & Differential:

WBC count (neutrophils >250/mm³ suggest SBP).

Lymphocytes (may indicate TB or malignancy).

Microbiological Tests:

Gram stain and culture for bacterial infection.

Cytology:

Detects malignant cells in suspected cancer cases.

Special Tests:

ADA (for TB), amylase (for pancreatitis), triglycerides (for chylous ascites).