Alpha-fetoprotein (AFP) is a protein produced primarily by the liver and yolk sac of a developing fetus during pregnancy. While levels are high in fetuses and decrease significantly by age 1, AFP testing is used in two distinct medical contexts: prenatal screening and tumor marker monitoring.
Lower than normal levels may indicate Down syndrome (trisomy 21) or Edwards syndrome (trisomy 18). alpha fetoprotein
It is a screening test, not a diagnostic one. A positive screen does not mean a definite abnormality; further diagnostics, such as an ultrasound or amniocentesis, are usually required. 2. Alpha-Fetoprotein (AFP) as a Tumor Marker Alpha-Fetoprotein (AFP) Test: MedlinePlus Medical Test Alpha-fetoprotein (AFP) is a protein produced primarily by