'''Alpha-fetoprotein''' (AFP) is a protein that is normally only produced in the
fetus during its development. When found in adults, it can be used as a
tumor marker. If high levels of AFP are found in amniotic fluid it can indicate a developmental defect in the baby.
Genetic counseling is usually offered if an
AFP screening test is positive.
Normal levels of alpha-fetoprotein in
blood plasma are very low, though they will go up slightly during
pregnancy. If levels are higher than this, it could possibly indicate that a
pathological process is occurring.
Like all
tumor markers, the detection of AFP by itself is not diagnostic of anything, although if it is detected it is certainly advisable to rule out the diseases could cause levels to rise. The primary reason tumour markers are used are to measure the success of a treatment (e.g.
chemotherapy), if levels of AFP are going down, it is an indication that a disease is improving.
High AFP in non-pregnant adult
The two most devastating conditions in an adult that cause elevated AFP in an adult are
testicular cancer and
hepatocellular carcinoma (HCC) (a type of liver cancer). Hepatocellular carcinoma will often increase AFP levels dramatically.
As well as these,
cirrhosis of the liver, and active
hepatitis also elevate levels of alpha-fetoprotein.
High AFP in amniotic fluid
An
amniocentesis can be done if an abnormality of a foetus is suspected.
Levels of AFP can be down slightly in Down's syndrome, and levels are frequently higher with neural tube defects such as
spina bifida.
A
multiple pregnancy, such as
twins or triplets, also causes an increase in AFP levels.
Category:Proteins
Category:Chemical pathology
es:Alfa-fetoproteína
fr:Alpha-fœtoprotéine