Description
Overview: While AFP is commonly tested in serum (blood) to screen for liver cancer or fetal defects, this specific test is performed on body fluids—typically ascites (fluid in the abdomen), pleural fluid (fluid around the lungs), or pericardial fluid.
Clinical Significance:
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Cancer Metastasis: High levels of AFP in a body fluid suggest that a tumor (specifically Hepatocellular Carcinoma or a Germ Cell Tumor) has spread to the lining of the abdomen or chest.
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Differential Diagnosis: It helps doctors differentiate between “benign” fluid buildup (caused by cirrhosis or infection) and “malignant” fluid buildup (caused by cancer).
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Gradient Analysis: Doctors often compare the AFP level in the fluid to the AFP level in the blood (Serum-Ascites Gradient) to make a precise diagnosis.
When is this test recommended?
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When a patient has unexplained fluid accumulation (ascites or pleural effusion).
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To rule out malignancy in patients with known liver disease (cirrhosis/hepatitis).
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To stage a cancer and check if it has spread to the peritoneum.
Sample Requirements:
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Specimen: Body Fluid (Ascites, Pleural, Peritoneal, etc.).
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Container: Red Top (Plain) Tube or a Sterile Screw-Cap Container. (Note: Gel tubes/SST are sometimes used depending on the lab, but plain tubes are preferred for fluids to avoid gel interference).
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Preparation: No fasting required. The sample is usually collected via a procedure called paracentesis (abdominal tap) or thoracentesis (chest tap).
