Ascitic Fluid Analysis Guidelines

Standard Tests

The European Association for the Study of the Liver (EASL), American Association for the Study of Liver Diseases (AASLD), and Korean Association for the Study of the Liver (KASL) recommend routine ascitic fluid analysis to include cell count and differential, albumin concentration, total protein concentration, and bacterial culture in blood culture bottles for all patients with ascites 1, 2, 3, 4
The cell count and differential is used to detect spontaneous bacterial peritonitis, with a focus on neutrophil count 1, 2, 4
Albumin concentration is used to calculate the serum-ascites albumin gradient, which helps to identify the cause of ascites 1, 2, 3
Total protein concentration is used to assess the risk of spontaneous bacterial peritonitis (SBP) 1, 2
Bacterial culture in blood culture bottles should be inoculated at the bedside to increase the yield of positive cultures 1, 2, 3

The EASL and AASLD recommend that additional tests, such as cytology, amylase, PCR and culture for mycobacteria, and adenosine deaminase (ADA), should only be performed when specific diagnoses are suspected based on clinical presentation and patient risk factors 1, 2, 4, 5
Cytology should be performed when malignancy is suspected, as it can help to identify cancer cells in the ascitic fluid 1, 2, 4
Amylase should be measured when pancreatic disease is suspected, as elevated levels can indicate pancreatic ascites 1, 2
PCR and culture for mycobacteria should be performed when tuberculosis is suspected, as these tests can help to identify Mycobacterium tuberculosis in the ascitic fluid 1, 2
Adenosine deaminase (ADA) should be measured for tuberculous peritonitis, with a sensitivity of 100% and specificity of 96.6-100% when >32-40 U/L in non-cirrhotic patients 5

Chinese ink staining is not a standard or recommended test for routine ascitic fluid analysis, but it can be used to visualize encapsulated organisms, such as Cryptococcus neoformans, in immunocompromised patients or when cryptococcal peritonitis is clinically suspected 5
The guidelines from EASL, AASLD, and KASL emphasize that other tests beyond the routine panel should only be ordered when there is specific clinical suspicion to avoid unnecessary costs and potential diagnostic confusion 1, 2, 3