The clinical value of serum alpha-fetoprotein

Alpha fetoprotein (AFP) is a major fetal serum globulin structurally and functionally related to albumin. During fetal development, AFP is produced sequentially by the fetal yolk sac, gastrointestinal tract, and liver. Thus normal production of AFP is unique to fetal development, making it an ideal marker for early fetal evaluation. Since its introduction into obstetric practice, maternal serum alpha-fetoprotein (MSAFP) screening has become the earliest non-invasive biochemical test to provide information regarding the fetus, thereby promoting access to earlier diagnosis, enabling families to make informed reproductive choices, and designing appropriate strategies for prenatal care and delivery. Normally, fetal AFP concentration levels continue to decrease through infantile stage (0 to 2 years), down to adult levels (0 – 8ng/ml). However, AFP is frequently re-expressed in patients affected by hepatocellular carcinoma (HCC) and yolk-sac tumors (YST) therefore used in clinical practice as a tumor marker. To improve the specificity of AFP, glycoforms of AFP are determined and used in the differential/early diagnosis, follow up of treatment and prognostication of patients with AFP secreting tumors. Alpha-fetoprotein is also used as a biochemical diagnostic and prognostic marker for prolonged jaundice in newborns.