Alpha-Fetoprotein (AFP) in Blood
How To Prepare
You do not need to do anything before
you have this test.
If you are pregnant, you will be weighed
before the blood test, because the test results will be based on your weight.
The test results are also based on race, age, and how many weeks you are in your
How It Is Done
The health professional drawing blood
- Wrap an elastic band around your upper arm to
stop the flow of blood. This makes the veins below the band larger so it is
easier to put a needle into the vein.
- Clean the needle site with
- Put the needle into the vein. More than one needle stick
may be needed.
- Attach a tube to the needle to fill it with
- Remove the band from your arm when enough blood is
- Put a gauze pad or cotton ball over the needle site as
the needle is removed.
- Put pressure on the site and then a
How It Feels
The blood sample is taken from a vein in
your arm. An elastic band is wrapped around your upper arm. It may feel tight.
You may feel nothing at all from the needle, or you may feel a quick sting or
You may feel anxious while awaiting results of an
alpha-fetoprotein test done to determine the health of your unborn baby.
There is very little chance of a problem from
having blood sample taken from a vein.
- You may get a small bruise at the site. You can lower the chance
of bruising by keeping pressure on the site for several minutes.
rare cases, the vein may become swollen after the blood sample is taken. This
problem is called phlebitis. A warm compress can be used several times a day to
- Ongoing bleeding can be a problem for people with
bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning
medicines can make bleeding more likely. If you have bleeding or clotting
problems, or if you take blood-thinning medicine, tell your doctor before your
blood sample is taken.
An alpha-fetoprotein (AFP) blood test
checks the level of AFP in a pregnant woman's blood. AFP is a substance made in
the liver of a developing baby (fetus). The amount of AFP in the blood
of a pregnant woman can help find certain problems with her baby.
The normal values listed here—called a reference range—are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, normal values vary with the age of the baby. A high or low AFP may mean
that the age of the baby has been recorded wrong or not calculated correctly.
ultrasound may be done to check the baby's age more