Neural tube defect
Chemiluminescent Immunoassay / Electrophoresis
82106 - Alpha-fetoprotein, amniotic
Within 5 days
2.5 mL amniotic fluid in a sterile container
Exposed to extreme heat
By report based upon weeks of gestation
When AFP levels are significantly elevated, reflex to Acetycholinesterase (AChE) testing to rule out a neural tube defect (NTD).
Alpha-fetoprotein (AFP) is found in both fetal serum and also amniotic fluid. This protein is produced early in gestation by the fetal yolk sac and then later in the liver and gastrointestinal tract. This protein’s level increases and decreases during certain weeks of pregnancy, which is why accurate pregnancy dating is crucial.
The AFP test measures high and low levels of alpha-fetoprotein. The results are combined with the mother’s age and ethnicity to assess probabilities of potential genetic disorders. High levels of AFP may suggest the developing baby has a neural tube defect such as spina bifida or anencephaly. High levels of AFP may also suggest defects with the esophagus or a failure of the baby's abdomen to close. Low levels of AFP and abnormal levels of hCG and estriol may indicate that the developing baby has Trisomy 21 (Down syndrome), Trisomy 18 (Edwards syndrome) or another type of chromosome abnormality.