Background

Testosterone is the principle androgen.  It is synthesized in the testes, the ovary and the adrenal cortex.  It is responsible for the development and maintenance of the male secondary sex characteristics.  It also exerts important anabolic and growth-promoting effects.  The plasma testosterone levels are useful in investigating hypogonadism and hormone replacement therapy in men.  It is also useful as a marker in hyper-androgenism in women.

Assay Principle

This is an ELISA for the quantitative analysis of Testosterone levels in biological fluid.  This test kit operates on the basis of competition between the hormone conjugate and the Testosterone in the sample for a limited number of binding sites on the antibody coated plate.

The sample or standard solution is first added to the microplate.  Next, the diluted hormone conjugate is added and the mixture is shaken and incubated at room temperature for one hour.  During the incubation, competition for binding sites is taking place.  The plate is then washed removing all the unbound material.  The bound hormone conjugate is detected by the addition of substrate which generates an optimal color after 30 minutes. Quantitative test results may be obtained by measuring and comparing the absorbance reading of the wells of the samples against the standards with a microplate reader at 450nm or 650nm.  The extent of color development is inversely proportional to the amount of Testosterone in the sample or standard.  For example, the absence of Testosterone in the sample will result in a bright blue color, whereas the presence of Testosterone will result in decreased or no color development.

If using urine as a sample it is recommended to run our

Creatinine Assay kit (CR01)

in conjunction with your samples since urinary creatinine levels may be used to normalize the rate of excretion of other analytes.