Development of an enzyme immunoassay for human placental lactogen using labelled antibodies

An immunoassay for the determination of human placental lactogen (HPL) has been developed using specific antibodies labelled with horseradish peroxidase. A method is presented in which the enzyme : antibody conjugate is purified with an antigenic solid phase to ensure the production of conjugates with intact immunological activity. Serum components interfere with the assay but this problem can only be avoided at the expense of a precise and practical assay for the determination of HPL.