The alpha-fetoprotein assay is useful for detecting and monitoring especially the therapeutic development of primary liver cancer (carcinoma hépathocellulaires).
This glycoprotein produced by the liver is the main protein of fetal serum; it happens physiologically in maternal blood;it is normally absent in adults.
Sampling 5 mL of blood in a dry tube.
The assay can also be performed from the puncture of ascites fluid.
The assay methods are used radioimmunoassay or enzyme immunoassay techniques.
– Adult: <20 ng / mL;
– Child from 10 000 to 100 000 ng / mL at birth, with a rapid decrease to the point that the adult rate is reached at the end of the first year;
– Pregnancy: <300 ng / mL at 32 weeks.
– Levels above 400 ng / mL were observed in 70% of liver carcinoma-type tumors, but such rates can be found in hepatitis or cirrhosis, and therefore can not be a reliable marker cancer; he must then confront biology and clinic for diagnosis (liver ultrasound).
– However, after removal of the tumor, AFP is a good way of monitoring a rate hike then being a sign of tumor recurrent disease;
– There is the same phenomenon in tumors non-seminoma testicular, where the elevation of AFP accompanies that of β-hCG;
– AFP is also increased in ovarian cancers, pancreas, stomach or bronchi;
– In case of fetal malformation, AFP is increased in amniotic fluid between the 14th and 16th week, especially for neural tube defects (spina bifida, anencephaly).
Pregnancy modifies the AFP rate results.