A radioimmunoassay of the pregnancy-specific beta1-glycoprotein (SP1).

A radioimmunological method for determination of the pregnancy specific beta1-glycoprotein (SP1) is described. Antigen specificity of rabbit anti-human SP1 serum (Behringwerke) was investigated against human placental and pituitary hormones. The sensitivity was about 10 microgram/l. The concentration ranges of SP1 in umbilical cord blood and amniotic fluid were 0.10--0.60 mg/l and 0.3--3.8 mg/l, respectively. A good correlation (r = +0.95) was found between the radioimmunological and electroimmunological methods for determination of SP1 in maternal blood.