A specific radioimmunologic assay for human placental alkaline phosphatase and its clinical applications

A radioimmunoassay specific for placental alkaline phosphatase (PALP) has been performed. Sera from blood donors contain less than 15 micrograms of PALP per liter. The amounts of PALP found in sera of pregnant women are higher, as soon as the first trimester of the pregnancy, increasing until delivery (50-600 micrograms of PALP L I). Only 3,5% of the patients with various cancer diseases have amounts higher than 25 micrograms PALP/I.