DETERMINATION OF STEROIDS BY COMPETITIVE IMMUNOASSAY

A method and kit for measurement of a steroid by means of a competitive immunoassay, preferably a competitive enzyme immunoassay. The method and kit involve the use of a steroid analogue conjugated to a label. The steroids that are amenable to detection by the method and kit of the present invention include estradiol and progesterone. The method comprises the steps of: a) incubating a mixture of a test sample suspected of containing a given steroid, a solid phase coupled to an antibody specific for that steroid, and a conjugate of an analogue of that steroid to form steroid/antibody complexes and conjugate/antibody complexes on said solid phase; b) separating said solid phase from said mixture; c) measuring the amount of label present in said mixture or in said solid phase; and d) determining the amount of steroid in said sample from the amount of label. The kit comprises a solid phase coupled to an antibody specific for a steroid and a conjugate of an analogue of that steroid.