Alpha-fetoprotein (AFP) is a serum protein produced by hepatocytes. AFP levels are used as a tumor marker for hepatomas and germ cell tumors, and the serum concentration has prognostic significance in other diseases. Levels of AFP is 0.6-9.3 kIU/L in blood from normal individuals under the age of 40. Concentrations raise with age and during pregnancy. AFP consists of one single polypeptide chain of 590 aminoacids with MW 65 kDa. This antibody is specific for human AFP. Cross-reactivity with other species or similar molecules has not been investigated.