The DetectX^® Corticosterone Enzyme Immunoassay Kit measures corticosterone present in serum, plasma, saliva, urine, extracted fecal samples, and tissue culture media. The kit has been developed for extracted fecal samples and has been validated with multiple animal species. Diluted samples are pipetted into a clear microtiter plate coated with an antibody. A corticosterone-peroxidase conjugate is added to the wells. The binding reaction is initiated by the addition of a polyclonal antibody to corticosterone. After an hour incubation the plate is washed and substrate is added. The substrate reacts with the bound corticosterone-peroxidase conjugate. After a short incubation, the reaction is read at 450nm.

Corticosterone is a glucocorticoid secreted by the cortex of the adrenal gland. Corticosterone is produced in response to stimulation of the adrenal cortex by ACTH and is the precursor of aldosterone. Corticosterone is a major indicator of stress and is the major stress steroid produced in non-human mammals. Studies involving corticosterone and levels of stress include impairment of long term memory retrieval, chronic corticosterone elevation due to dietary restrictions and in response to burn injuries. In addition to stress levels, corticosterone is believed to play a decisive role in sleep-wake patterns.