Can you draw ascites for a D-dimer test from a device in a patient with ascites?

D-Dimer Testing from Ascitic Fluid: Not Recommended

D-dimer testing should not be performed on ascitic fluid obtained via paracentesis, as this test is not validated for ascitic fluid analysis and has no established clinical utility or diagnostic value in evaluating ascites.

Why D-Dimer is Not Part of Standard Ascitic Fluid Analysis

The established guidelines for ascitic fluid analysis do not include D-dimer testing because it provides no diagnostic information for the conditions that cause or complicate ascites:

Standard Ascitic Fluid Tests (What Should Be Ordered)

Essential tests that should be performed on all diagnostic paracentesis samples include 1:

• Cell count with differential (particularly neutrophil count to diagnose spontaneous bacterial peritonitis when PMN >250 cells/µL)
• Total protein and albumin concentration (to calculate serum-ascites albumin gradient)
• Culture (bedside inoculation of at least 10 mL into blood culture bottles)

Optional tests based on clinical suspicion include 2, 3:

• Cytology (for suspected malignancy)
• Adenosine deaminase (ADA) for tuberculous peritonitis
• Triglyceride level (for chylous ascites)
• Glucose and LDH (when secondary peritonitis is suspected)
• Amylase (for pancreatic ascites)

Why D-Dimer Has No Role

D-dimer is a serum marker used to evaluate for thrombotic disorders and is measured in blood, not peritoneal fluid 2. The test has:

• No validated reference ranges for ascitic fluid
• No established diagnostic utility for any ascites-related condition
• No mention in any major hepatology or gastroenterology guidelines for ascites evaluation 1

Critical Clinical Pitfall to Avoid

Do not order unnecessary tests on ascitic fluid 3. The practice of ordering a battery of tests on every ascitic fluid specimen should be abandoned in favor of an algorithmic approach where initial results guide selective additional testing 3. Ordering non-validated tests like D-dimer:

• Wastes healthcare resources
• May delay appropriate diagnosis and treatment
• Can lead to confusion when interpreting meaningless results

What to Do Instead

If you suspect a thrombotic complication (such as portal vein thrombosis) in a patient with ascites:

• Order serum D-dimer from a blood sample, not ascitic fluid
• Obtain Doppler ultrasound or CT imaging to directly visualize vascular thrombosis 4
• Perform standard ascitic fluid analysis as outlined above to determine the cause and complications of the ascites 1