Albumin, Fluid

What it is:
This test measures the level of albumin, a major protein made by the liver, in body fluids such as pleural fluid (around the lungs), peritoneal fluid (ascites), or cerebrospinal fluid (CSF). Comparing fluid albumin with serum albumin helps determine the cause of fluid accumulation.

Uses

• Differentiate between transudative and exudative effusions (using the Serum-Ascites Albumin Gradient or SAAG, and Light’s criteria)

• Diagnose conditions causing fluid buildup, such as:

  • Cirrhosis and portal hypertension

  • Heart failure

  • Infections (e.g., TB, bacterial peritonitis, pneumonia)

  • Cancers (malignant effusions)

Symptoms That May Lead to the Test

• Abdominal swelling (ascites)

• Shortness of breath (pleural effusion)

• Unexplained swelling/edema

• Signs of infection, cancer, or chronic liver disease

Abnormal Results

• High fluid albumin (relative to serum):

  • Suggests transudate → conditions like cirrhosis, nephrotic syndrome, or heart failure

• Low fluid albumin (relative to serum):

  • Suggests exudate → infections (TB, pneumonia), malignancy, or inflammatory conditions

Risks

• Risks depend on the fluid collection procedure:

  • Paracentesis (abdomen) / Thoracentesis (chest) / Lumbar puncture (CSF):

    • Mild pain or discomfort

    • Rare bleeding or infection

    • Very rarely injury to nearby organs