The B-Bridge Allopregnanolone Immunoassay kit is designed to quantitatively measure Allopregnanolone present in extracted serum, plasma, and dried fecal samples, and in urine and tissue culture media samples. An allopregnanolone standard is provided to generate a standard curve for the assay and all samples should be read off the standard curve. Standards or diluted samples are pipetted into a clear microtiter plate coated with an antibody to capture rabbit antibodies. An allopregnanolone-peroxidase conjugate is added to the wells. The binding reaction for the EIA/ELISA is initiated by the addition of a polyclonal antibody to allopregnanolone to each well. After incubation the plate is washed and substrate is added. The substrate reacts with the bound allopregnanolone-peroxidase conjugate. After a short incubation, the reaction is stopped and the intensity of the generated color from the EIA/ELISA is detected in a microtiter plate reader capable of measuring 450nm wavelength.