Corticosterone Chemiluminescent Immunoassay (CLIA) kit is designed to quantitatively measure Corticosterone present in extracted dried fecal samples, serum, plasma and tissue culture media samples. This kit measures total corticosterone in serum and plasma and in extracted fecal samples. A corticosterone standard is provided to generate a standard curve. Standards or diluted samples are pipetted into a white microtiter plate coated with an antibody to capture sheep antibodies. A corticosterone-peroxidase conjugate is added to the standards and samples in the wells. The binding reaction is initiated by the addition of a sheep polyclonal antibody to corticosterone to each well. After a two hour incubation the plate is washed and the chemiluminescent substrate is added. The substrate reacts with the bound corticosterone-peroxidase conjugate to produce light.