List the information that can be obtained from ascitic fluid analysis. What are your indications for an ascitic fluid tap?
Ascitic fluid analysis provides – Fluid for General appearance
Albumin / protein content
Red cell count White cell count Culture and sensitivity Cytology
Biochemistry - amylase
Indications for performing a tap include: any patient with ascites and PUO, critical illness or suspected malignancy.
I would expand the college list:
Information which can be derived from an ascitic fluid analysis:
- Appearance - turbidity would be very suspicious for SBP
- Albumin - to calculate serum/ascites albumin gradient
- Amylase/lipase - to consider pancreatitis as the cause of ascites
- LDH (low indicates hepatic cause, whereas >500 suggests malignancy)
- Gram stain - for bacteria
- India ink stain - for hyphae
- ZN stain for acid-fast bacilli (tuberculosis)
- Flow cytometry and cell count - RBC/WCC ratio would raise suspicion of SBP
- Cytology - presence of malignant cells
- alpha-foetoprotein - to investigate for HCC
Indications for ascitic fluid drainage:
- see above
- patient discomfort
- respiratory compromise due to adominal pressure
- abdominal compartment syndrome
- infected ascitic fluid (i.e. as source control)
- for peritoneal dialysis (this can be viewed as a therapeutic paracentesis
Bar-Meir, Simon, Emanuel Lerner, and Harold O. Conn. "Analysis of ascitic fluid in cirrhosis." Digestive diseases and sciences 24.2 (1979): 136-144.
Boyer, Thomas D., Arthur M. Kahn, and Telfer B. Reynolds. "Diagnostic value of ascitic fluid lactic dehydrogenase, protein, and WBC levels." Archives of internal medicine 138.7 (1978): 1103-1105.
Runyon, Bruce A., John C. Hoefs, and Timothy R. Morgan. "Ascitic fluid analysis in malignancy‐related ascites." Hepatology 8.5 (1988): 1104-1109.