List the information  that  can  be obtained  from  ascitic  fluid  analysis.    What are  your indications for an ascitic fluid tap?

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College Answer

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.

Discussion

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)
  • Culture/sensitivities
  • 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:

  • Diagnostic
    • see above
  • Therapeutic
    • 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

References

References

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.