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Alpha-fetoprotein (AFP) is the major protein found in fetal serum, similar in size and several other characteristics to albumin in adult blood. AFP is normally present in adult blood but in very low amounts.

During pregnancy, even though the maternal and fetal blood streams are separate, small amounts of AFP leak into the maternal system, the amount varying with the gestational age.

If unusually large amounts of AFP are found in the maternal blood stream (>2.5 MOM or multiples of the mean), this may indicate:

  • Fetal neural tube defect, such as spina bifida, anencephaly, or encephalocele
  • Malformation of the fetal GI tract
  • Malformation of the fetal abdominal wall
  • Normal twin pregnancy
In pregnancies in which the baby has Down syndrome the levels are on average reduced to 0.7 MOM.

Elevations may be found in:

  • Any traumatic injury to any of these structures
  • Any disease affecting one of these structures
  • Cirrhosis (large increase)
  • Liver metastasis (large increase)
  • Liver abscess (large increase)
  • Obstructed bile duct (large increase)
  • Bone cancers (large increase)
  • Hepatitis (moderate increase)
  • Hepatitis (moderate increase)
  • Pancreatitis (moderate increase)
  • Infectious mononucleosis
  • Hyperparathyroidism

Decreased amounts may be found in:

  • Malnutrition
  • Hypothyroidism
  • Pernicious anemia
  • Vitamin C deficiency

Normal Values*



<15 Ku/L
Pregnancy Varies with gestational age

*These are general values taken from a variety of sources. The actual normal values may vary from lab to lab and from one type of testing protocol to another.




Source: Operational Medicine 2001,  Health Care in Military Settings, NAVMED P-5139, May 1, 2001, Bureau of Medicine and Surgery, Department of the Navy, 2300 E Street NW, Washington DC, 20372-5300, USA