- What is the AFP test?
- When is the AFP test performed?
- What preparation is needed for the AFP test?
- How is the AFP test performed?
- How are AFP test results interpreted?
It is a blood test aiming at detecting the levels of alpha-fetoprotein (AFP) in the blood. AFP is a protein which is normally produced by the fetal liver, yolk sac and gastrointestinal tract. The APF levels gradually decrease after birth. In adults it is normally detected at very low levels. High AFP levels in adults may be due to hepatocellular carcinoma, some types of cancer in the testes, ovaries and -more rarely- stomach, pancreas and lungs.
In Urology the AFP test must be done in every case of testicular cancer before surgical removal. Although cancer is diagnosed with patho-anatomical examination of the testes, the detection of high preoperative AFP levels has clinical value for the staging of the disease. Taken into account together with other factors, it also helps in determining the appropriate treatment and monitoring the patient.
The AFP test is conducted postoperatively:
- For staging the disease. Persistent high AFP levels after orchiectomy (removal of testis) indicate that somewhere in the body there are metastatic cells that keep secreting the alpha-fetoprotein.
- For treatment evaluation. If successful, AFP levels should become normal.
- For detecting cancer relapse. If AFP levels become normal after therapy and then start increasing again, this indicates that the tumor has probably recurred.
No special preparation is needed. All that is needed is simply taking a small blood sample before the surgical removal of the testis.
Once obtained, the blood sample is taken to the biochemical laboratory. AFP is estimated with the use of special analyzers.
The normal alpha-protein values for men are 0-7 ng/ml. In testicular cancer, every value over 7ng/ml should be evaluated by the therapist physician.