The B-Bridge Prolactin kit is designed to quantitatively measure Prolactin present in biological samples and tissue culture media. The kit has been tested to measure human and elephant prolactin. Other species have not been measured. A human Prolactin standard is provided to generate a standard curve for the assay. Standards or diluted samples are pipetted into a clear microtiter plate coated with a monoclonal antibody to Prolactin. After a 60 minute incubation, the plate is washed and a peroxidase conjugated Prolactin polyclonal antibody is added. The plate is again incubated for 60 minutes and washed. Substrate is then added to the plate, which reacts with the bound Prolactin Antibody Conjugate. After a third incubation, the reaction is stopped and the intensity of the generated color is detected in a microtiter plate reader capable of measuring 450 nm wavelength.