A multi-center evaluation of a new immunoenzymometric assay for human choriogonadotropin

A new, rapid, monoclonal immunoenzymometric assay for human choriogonadotropin (HCG), the Enzymun-Test HCG (Boehringer Mannheim GmbH), was evaluated by 15 laboratories in 10 European countries. Inter-assay percent CVs ranged from 5.4 to 40.5, 2.4 to 15.4, and 2.3 to 17.1 for low, medium, and high dose sera, respectively. Mean assay sensitivity was 0.34 mIU/mL HCG. Analytical recovery in serum ranged from 75 to 119%. Serial dilutions of HCG in normal human serum and in assay zero standard were found to be linear. Cross-reactivity with lutropin, follitropin, and thyrotropin was negligible. Serum reference values were established for normals and all stages of pregnancy. Comparative studies with nine other HCG immunoassays were carried out using a range of normal, pregnancy, and tumour sera. We conclude that this is an acceptable assay for monitoring HCG-producing tumours and pregnancy.