Alpha fetoprotein

Definition

Alpha fetoprotein (AFP) is a protein produced by the liver and yolk sac of a developing baby during pregnancy. AFP levels go down soon after birth. It is likely that AFP has no normal function in adults.

A test can be done to measure the amount of AFP in your blood.

Alternative Names

Fetal alpha globulin; AFP

How the Test is Performed

A blood sample is needed. Most of the time, blood is typically drawn from a vein located on the inside of the elbow or the back of the hand.

How to Prepare for the Test

You do not need to take any special steps to prepare.

How the Test will Feel

You may feel slight pain or a sting when the needle is inserted. You may also feel some throbbing at the site after the blood is drawn.

Why the Test is Performed

Your health care provider may order this test to:

  • Screen for problems in the baby during pregnancy. (The test is done as part of a larger set of blood tests called quadruple screen.)
  • Diagnose certain liver disorders.
  • Screen for and monitor some cancers.

Normal Results

The normal values in males or nonpregnant females is generally less than 40 micrograms/liter.

The examples above are common measurements for results of these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your provider about the meaning of your specific test results.

What Abnormal Results Mean

Greater than normal levels of AFP may be due to:

Images

Blood test
Alpha fetoprotein - series

References

Driscoll DA, Simpson JL, Holzgreve W, Otano L. Genetic screening and prenatal genetic disgnosis. In: Gabbe SG, Niebyl JR, Simpson JL, et al, eds. Obstetrics: Normal and Problem Pregnancies. 7th ed. Philadelphia, PA: Elsevier; 2017:chap 10.

Fundora J. Neonatology. In: Hughes HK, Kahl LK, eds. The Johns Hopkins Hospital: The Harriet Lane Handbook. 21st ed. Philadelphia, PA: Elsevier; 2018:chap 18.

Wapner RJ. Prenatal diagnosis of congenital disorders. In: Creasy RK, Resnik R, Iams JD, Lockwood CJ, Moore TR, Greene MF, eds. Creasy and Resnik's Maternal-Fetal Medicine: Principles and Practice. 7th ed. Philadelphia, PA: Elsevier Saunders; 2014:chap 30.

Review Date: 
8/26/2017
Reviewed By: 
Peter J Chen, MD, FACOG, Associate Professor of OBGYN at Cooper Medical School at Rowan University, Camden, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

Related Health Topics