We have developed immunoassays, monitored by the detection of chemiluminescence, for measuring choriogonadotropin in human urine. These methods involve the use of derivatives of isoluminol and include: (a) a labeled antigen with a second antibody covalently linked to polyacrylamide beads as the solid-phase reagent (i.e., solid-phase chemiluminescence immunoassay); and (b) an excess concentration of a specific antibody passively adsorbed onto the walls of polystyrene tubes and a labeled antibody of different specificity (i.e., two-site immunochemiluminometric assay). After the respective binding reactions, the solutions are aspirated, the antigen- or antibody-bound fractions are washed twice with 500 microL of buffer, sodium hydroxide (2 mol/L; 200 microL) is added, and the mixture is incubated for 60 min at 60 degrees C. After cooling, the label is oxidized with microperoxidase/hydrogen peroxide and the resulting chemiluminescence signal is measured for 10 s. We have evaluated the methods in terms of their sensitivity, precision, and clinical utility, and we compare results with values obtained by radioimmunoassay.