AFP (Alpha fetoprotein) Test

AFP Test measures the level of alpha fetoprotein in blood. Alpha fetoprotein is found  high in pregnants and its level decreases quickly after birth. AFP test shows any chromosomal or development abnormalities in baby. AFP  is one of the tests that is done with the triple and quadruple screening tests. Healthy people have low levels of AFP in blood but its level increases in liver damage and some kinds of cancers. AFP test is used to monitor the treatment of chronic liver diseases like cirrhosis or hepatitis.

AFP production

AFP is produced during pregnancy by fetus. In earlier weeks of pregnancy it is produced from yolk sac but in following weeks  it is mainly production place is baby’s liver. AFP is produced by baby’s liver and passes to mother’s blood circulation.

How the AFP test is performed

Same as other blood tests a blood collection procedure will be needed for AFP test. This is short and easy process and you don’t need to worry about. Your nurse/technician will insert a needle into your arm vein (usually arm veins are used) you may feel a little pain for a few seconds during the process. Then a tube of blood will be collected for the test. This blood collection process has no risk for you and your baby.

AFP (Alpha fetoprotein)

Factor that may affect AFP test results

  • Gestational diabetes
  • Radioactive screening tests in last 2 weeks
  • Smoking
  • Multiple pregnancy (twins,triplets)
  • Mother’s weight; AFP level may be found low in overweight pregnants so mother’s weight should be known during the test evaluation
  • AFP levels are found higher in black race but neural tube defect risk is low

Why the AFP test is done?

AFP test is done between the 16-20 weeks of pregnancy for screening some problems in baby. Also AFP test is used to diagnose some diseases in adults.

  • Screening the unborn baby for neural tube defects that are brain and spinal abnormalities,usage of folic acid decreases the neural tube defect risk
  • Determination the Down Syndrome risk of developing baby
  • Screening cancer types for both men and women; testicular cancer and ovarian cancer
  • Determination of liver cancer
  • Monitoring the treatment for the cancer types above
  • Determination these cancers whether they  are relapsed

AFP Test normal values

These values may change according to the laboratory, test method and the analyser

Men: 0-40 ng/mL

Nonpregnant women: 0-40 ng/mL

Pregnant women: 10-150 ng/mL

When AFP level increases in pregnancy ?

AFP level increases from 14 weeks of pregnancy and stays in these levels till 2 months from birth then AFP level starts to decrease slowly. For a healthy evaluation of AFP level, baby’s correct age must be known.

High AFP test results causes

  • Baby’s age may be wrong
  • Multiple pregnancies like twins, triplets
  • Neural tube defects
  • Abdominal wall defect of baby; baby’s intestines and other organs may be developing outside the body
  • Testis cancer
  • Ovarian cancer
  • Stomach cancer
  • Pancreas cancer
  • Liver cancer
  • Liver diseases like cirrhosis or hepatitis
  • Chronic alcoholism

Low AFP test result causes

  • Baby’s age( gestational age) may be calculated wrong
  • There can be a birth defect like down syndrome


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