The AFP Serum test is a single blood test with two vital, distinct purposes. 1) For adults: It is a primary tumor marker used to help diagnose and monitor certain cancers, most notably liver cancer (HCC) and testicular cancer. 2) For expectant mothers: It is a key part of the prenatal screening (like the Triple or Quadruple Marker test) to assess the risk of fetal neural tube defects, such as spina bifida. This powerful blood test provides critical, actionable information for two very different, but equally important, health journeys.