Analysis of ascites fluid by paracentesis is performed to accomplish which goal?

• A. Determine the cause of fluid presence and assess infection risk
• B. Determine the cause of fluid presence
• C. Assess infection risk
• D. Determine lung involvement

Answer: (A)

Analyzing ascitic fluid from paracentesis serves two main purposes: to determine why fluid has accumulated in the abdomen and to assess the risk of infection. The serum-ascites albumin gradient (SAAG) helps distinguish portal hypertension–related ascites (high gradient) from other causes (low gradient). A high SAAG points toward cirrhosis, heart failure, or related conditions as the cause, while a low SAAG suggests non–portal hypertension etiologies such as infection, malignancy, pancreatitis, or nephrotic syndrome. Beyond this, the fluid’s cell count and differential, total protein, LDH, and microbiological studies (Gram stain, culture) help identify or exclude infection, notably spontaneous bacterial peritonitis when neutrophil counts are elevated. Lung involvement is not assessed by ascitic fluid analysis; that would require separate pulmonary evaluation.