ascitic fluid analysis

Introduction

Analysis of peritoneal fluid obtained from paracentesis

Indications

ascites of unknown etiology

Procedure

• cell count
  • WBC > 250/mm3 with neutrophils & bands suggests bacterial peritonitis
  • lymphocytic predominance occurs in tuberculous peritonitis & peritoneal carcinomatosis
  • correct cell count for RBC, use RBC/WBC ratio from CBC
• ascitic fluid protein
  • < 1.0 g/dL suggests high risk for spontaneous bacterial peritonitis
  • total protein is low <2.5 g/dL in cirrhotic ascites & high >= 2.5 g/dL in cardiac ascites
• albumin
  • [[[A19127|serum]] albumin] - [ascitic fluid albumin] > 1.1 g/dL is consistent with portal hypertension
    • hepatic cirrhosis
    • liver metastasis
    • hepatic failure
    • alcoholic hepatitis
    • Budd-Chiari syndrome
    • right heart failure or constrictive pericarditis
      • ascitic fluid total protein > 2.5 g/dL
    • portal vein thrombosis (portal hypertension)
    • myxedema
    • fatty liver of pregnancy
    • hepatic veno-occlusive disease
  • [[[A19127|serum]] albumin] - [ascitic fluid albumin] < 1.1 g/dL
    • peritoneal carcinomatosis
    • biliary ascites
    • tuberculous ascites
    • pancreatitis
    • nephrotic syndrome
    • bowel obstruction with infarct
    • postoperative lymphatic leakage
    • serositis seen in connective tissue disease
    • less useful in patients with known hepatic cirrhosis
• culture
  • most bacterial peritonitis is caused by a single organism
  • anaerobic & aerobic cultures
• amylase
  • increased ascitic fluid amylase with pancreatitis & bowel perforation
  • levels generally 3-5 times serum levels
• tuberculosis testing
  • tuberculous peritonitis is often associated with negative cultures from ascitic fluid
  • predominance of mononuclear cells in ascitic fluid
  • laparoscopy with histologic analysis of biopsy specimens is more sensitive for tuberculous peritonitis
• cytology
  • less sensitive where tumor cells do not line the peritoneal cavity, i.e. lymphoma, hepatoma
• triglycerides when cloudy fluid suggests chylous ascites
• bilirubin > 6 mg/dL & > [[[A19127|serum]] bilirubin] suggests biliary or upper GI perforation

More general terms

• chemistry panel
• hematology panel
• microbiology panel

Additional terms

• ascites
• paracentesis