AFP (Alpha-Fetoprotein)
Definition
AFP is a protein produced by the liver while liver cells grow and divide. Its level is high in the fetus and drops markedly after birth.
Purpose
There are two different tests, and they should not be confused:
| Test | Purpose |
|---|---|
| AFP tumor marker | Monitoring in patients diagnosed with or being treated for liver, ovarian or testicular cancer |
| AFP in pregnancy | A separate test; it assesses the risk of certain birth defects in the fetus and is not a cancer screen |
Results
- High (when not pregnant), may be liver, ovarian or testicular cancer; however, non-cancerous liver disease can also raise it
- Normal, a cancer that raises AFP is unlikely, but not excluded
- Falling during treatment, treatment is working
- Rising after treatment, may be recurrence
Normal Values
Laboratory specific.
Risks and Limitations
- Cannot diagnose cancer on its own; imaging (ultrasound, CT, MRI) is required
- AFP is normal in some cancer patients
- Non-cancer causes: cirrhosis, hepatitis B and C