Alpha-fetoprotein (AFP) test
Alpha-fetoprotein (AFP) is a protein normally made by the yolk sac, intestines and liver of a developing fetus. AFP levels go down soon after birth, so healthy children and adults usually have very little AFP in their blood. Certain types of cancer may cause an increase in the amount of AFP in the blood. A higher level of AFP in the blood may also mean that there is something wrong with the liver.
Why an AFP test is done
Your healthcare team may order an AFP test for different reasons. For the following cancers, it can help with diagnosis, measuring your response to treatment and checking if the cancer has come back (recurred):
- non-seminomatous testicular cancer
- ovarian germ cell cancer
- extragonadal germ cell cancer (a type of cancer that develops from germ cells outside of the
gonads ) - liver cancer
In some cases, an AFP test can be used to help diagnose the following cancers:
- bile duct
- stomach
- colon
- pancreas
- lung
- lymphoma
- childhood central nervous system (CNS) germ cell cancer (for example, non-germinatous germ cell tumours)
cancer of unknown primary (CUP)
You may also have an AFP test to help manage liver problems such as cirrhosis or infection with hepatitis virus B or C.
During pregnancy, an AFP test may be done to screen for birth defects or genetic disorders.
How an AFP test is done
AFP is measured in a sample of blood taken through a needle. An AFP test is usually done in a private or hospital lab. No special preparation is needed.
What the results mean
Your healthcare team will look at the results of your AFP test, along with other test results, to help diagnose and treat you.
Higher than normal AFP levels in the blood may be a sign of a germ cell tumour or liver cancer. These types of cancer can release AFP into the blood.
AFP may also be higher than normal with one of the following non-cancerous conditions:
- cirrhosis
- hepatitis
- a rare inherited disorder called
ataxia-telangiectasia
For some people, a slightly higher AFP level may be normal.
Your healthcare team may repeat the measurement of AFP in your blood to check your response to cancer treatment. If the AFP level was high before treatment, lower AFP levels may mean that the cancer has responded to the treatment. If the AFP levels get higher, it may mean that the cancer is not responding well to treatment, is still growing or has come back (recurred).
What happens if a change or abnormality is found
The healthcare team will decide if more tests, procedures, follow-up care or additional treatment is needed.
Special considerations for children
Preparing children for a test or procedure by explaining what will happen during the test, such as what the child will see, feel and hear, can be very helpful. Preparing children before a test or procedure can help lower their anxiety, make them more cooperative and develop their coping skills.
How you prepare your child for an AFP test depends on your child's age and experience. Find out more about helping your child cope with tests and treatments.