Alpha-Fetoprotein (AFP)

Function

Alpha-Fetoprotein (AFP) is a protein produced primarily by the liver and yolk sac of a developing fetus. In healthy non-pregnant adults, AFP levels are typically very low or undetectable. However, AFP serves as a critical biomarker in two primary medical contexts: oncology and obstetrics.

Why it is Ordered

In oncology, doctors order the AFP test to screen for, diagnose, or monitor treatment for certain types of cancers. It is most commonly used for Hepatocellular Carcinoma (liver cancer) and germ cell tumors of the ovaries or testes. In chronic liver disease patients (such as those with Hepatitis B or C), rising AFP levels can be an early warning sign of malignant transformation. In obstetrics, it is part of the 'quad screen' to assess the risk of neural tube defects or chromosomal abnormalities in the fetus.

Associated Conditions

High levels of AFP are associated with several conditions:

• Hepatocellular Carcinoma: Primary liver cancer.
• Germ Cell Tumors: Non-seminomatous germ cell tumors of the testes or ovaries.
• Liver Cirrhosis/Hepatitis: Chronic inflammation can cause moderate elevations.
• Pregnancy Complications: Abnormally high levels in maternal blood may indicate neural tube defects (like spina bifida), while low levels might suggest Down Syndrome.