Testosterone free ELISA

Background:Testosterone is found in circulation predominantly linked to carrier proteins, the most common of which being sex-hormone binding globulin (SHBG). Testosterone plays a key role in the development of primary and secondary sexual characteristics in males and is involved in the production of female sexual hormones. Only 1 – 2% of testosterone in circulation is not bound to any protein and is biologically active – this is referred to as ‘free testosterone’ (FT). Bioavailable testosterone refers to the sum of FT and the testosterone bound to serum albumin, since it is bound with low affinity and readily able to dissociate to become available for its biological function. In males elevated levels of testosterone are associated with several conditions such as, early (precocious) puberty, congenital adrenal hyperplasia (CAH), androgen insensitivity syndrome (AIS), steroid use and testicular or adrenal tumours. Whereas the major causes of supressed levels include Klinefelter’s syndrome, testicular damage, pituitary disorders etc. In females of all ages, elevated testosterone levels can be associated with a variety of virilising conditions including adrenal tumours and polycystic ovarian syndrome (PCOS). These clinical conditions are associated with either a lack or excess of testosterone in circulation (hypoandrogenism or hyperandrogenism). Diagnosis of these disorders involve the quantification of total testosterone (TT) in association with other clinical evidence and laboratory data. However, clinical manifestations of androgen disorders are often associated with normal levels of TT. In such cases, additional information may be gained by the assessment of the biologically active, FT level. Several androgen disorders can be caused by alteration of SHBG production which affects the levels of FT available in serum. Measurement of FT can be considered useful in the diagnosis of several conditions including androgen deficiency in men and androgen excess in women. Assessment of free testosterone levels may prove beneficial and may avoid an incorrect diagnosis of hypogonadism in cases when low concentrations of total testosterone are determined and alterations of SHBG are suspected. There is an observed and well documented circadian variation of testosterone levels in men with circulating concentrations being higher in the morning and declining throughout the day. Testosterone levels also decline in ageing males (andropause) and is associated with loss of muscle and bone mass, leading to osteoporosis, loss of libido, erectile dysfunction. Depression and impaired cognitive function.

Description:
The Free Testosterone ELISA is a competitive enzyme immunometric assay (ELISA) where free testosterone (antigen) in the sample competes with the antigenic testosterone conjugated with horseradish peroxidase (HRP) for binding to the limited number of antibodies anti- testosterone coated on the microplate (solid phase).After the incubation, the bound/free separation is performed by a simple solid phase washing. Then, the enzyme HRP in the bound fraction reacts with the Substrate (H2O2) and the TMB Substrate and develops a blue colour that changes into yellow when the Stop Solution (H2SO4) is added. The colour intensity is inversely proportional to the free testosterone concentration of in the sample.Free testosterone concentration in the sample is calculated through a calibration curve.

Product features:
The kit contains reagents for 96 determinations;
Microtiter plate consisting of 12x8 (breakapart);
Microtiter plate reader at 450/620 nm;
Assay measuring range: 0,34 – 70 pg/mL;
IVD.