Development of radioimmunoassay for pregnancy-specific beta1-globulin and its measurement in serum of patients with trophoblastic and non-trophoblastic tumours.

Levels of human pregnancy-specific or trophoblast-specific beta1-globulin (TBG) were measured by double-antibody radioimmunoassay (RIA) in 103 patients with trophoblastic tumours and in 114 patients with a variety of non-trophoblastic tumours. The sensitivity of RIA for TBG was about 1 ng per ml. Twenty healthy adult females and males had levels below 1 ng per ml. Using the RIA for measurement of TBG in sera which were selected from immunodiffusion-TBG-negative samples, we detected elevated TBG levels in 76.7% of cases with trophoblastic tumours and in 15% of different cases with non-trophoblastic malignancies. The diagnostic and prognostic significance of the measurement of TBG levels by RIA in patients with trophoblastic tumours is discussed.