Two questions:
- Is the fluid infected?
- Is portal hypertension present?
Tests:
- Appearance assessment
- Clear - Uncomplicated ascites in the setting of cirrhosis is usually translucent yellow
- Bloody - traumatic tap, malignancy
- Cloudy - Infected fluid, spontaneous bacterial peritonitis
- Milky - Chylous ascites, Malignancy, cirrhosis, and lymphatic disruption after abdominal surgery
- Serum-to-ascites albumin gradient (SAAG)
- Subtracting the ascitic fluid albumin value from the serum albumin value
- Gradient <11 g/L indicates that the patient does not have portal hypertension
- Gradient ≥11 g/L predicts that the patient has portal hypertension
- Cell count and differential
- Identifies infected ascitic fluid
- Total protein concentration
- Ascitic fluid can be classified as an exudate if the total protein concentration is ≥2.5 or 3 g/dL and a transudate if it is below this cutoff.
- Exudate/transudate system of ascitic fluid classification has been replaced by the SAAG, which is a more useful measure for determining whether portal hypertension is present
- Gram stain
- Cytology
- Amylase - raised in pancreatic ascites
Procedure:
- Left lower quadrant - 2 finger breaths in and up from ASIS
- Mark the site
- Prep and drape
- Local anaesthetic
- Needle is placed
- Aspirate
Complications
- Ascitic fluid leak
- Bleeding
- Bowel perforation
- Infection
- Death