Description

The Diagnostic Automation, Inc. Free Testosterone ELISA kit is for quantitative determination of Free Testosterone concentration in serum and plasma. Testosterone is primarily secreted in the testes of males and the ovaries of females although small amounts are secreted by the adrenal glands. It is the principal male sex hormone and an anabolic steroid. In both males and females, it plays key roles in health and well-being. Only 1-2% of circulating testosterone exists as unbound or free testosterone. The majority, approximately 60%, is bound to SHBG with high affinity, while the remainder is loosely bound to albumin. Both the albumin-bound and free fractions may be biologically active, while SHBG effectively inhibits testosterone action.

Testosterone effects can be classified as virilizing and anabolic effects. Anabolic effects include growth of muscle mass and strength, increased bone density and strength, and stimulation of linear growth and bone maturation. Virilizing effects include maturation of the sex organs. Testosterone levels decline gradually with age in men. Measurement of the free or unbound fraction of serum testosterone has been proposed as a means of estimating the physiologically bioactive hormone. Free testosterone levels are elevated in women with hyperandrogenism associated with hirsutism in the presence or absence of polycystic ovarian disease. In addition, free testosterone measurements may be more useful than total testosterone in situations where SHBG is increased or decreased (e.g. hypothyroidism and obesity).

Free Testosterone(antigen) in the sample competes with horseradish peroxidase testosterone (enzyme labeled antigen) for binding onto the limited number of anti- testosterone (antibody) sites on the microplates (solid phase). After incubation the bound/free separation is performed by a simple solid-phase washing. The enzyme substrate (H2O2) and the TMB-Substrate (TMB) are added. After an appropriate time has elapsed for maximum color development, the enzyme reaction is stopped and the absorbance is determinated. Free Testosterone concentration in the sample is calculated based on a series of standard. The color intensity is inversely proportional to the Free Testosterone concentration of in the sample. Testosterone in the blood is bound to SHBG (60 %) and in lower quantity to other protein. Only the measurement of Free Testosterone (< 1% of Total Testosterone) permits the estimating of the hormone biologically active.