Free Testosterone ELISA Kit


Human free testosterone ELISA kit is a reliable quantitative procedure for measuring unbound free testosterone in human serum and plasma samples. This assay has a minimum sensitivity detection limit of 0.06 pg/ml.


Testosterone is a C19 steroid hormone that belongs to the androgen group, these are secreted in the testes of males and in the ovaries of females. The levels are found to gradually decline with age in men and its effects are essentially classified as virilizing and anabolic effects. Virilizing effects include maturation of the sex organs, whilst anabolic effects include growth of muscle mass and strength, stimulation of linear growth and bone maturation and increased bone density and strength.

Since testosterone is insoluble in aqueous solutions, majority of it is found to circulate the blood by binding to transport proteins, there is usually only a small fraction (< 1%) which exists as unbound (free testosterone). Approximately 60% of it is bound to SHBG with high affinity, whilst the remainder is loosely bound to albumin. It is the albumin-bound and free fractions which represent the biologically active forms, whilst SHBG is known to effectively inhibit testosterone action. The determination of unbound or free fraction is a useful means of estimating the physiologically bio-active hormone. Other uses for measuring unbound/free is in situations where SHBG levels are increased or decreased for example during hypothyroidism and obesity.


All reagents supplied need to be stored at 2 °C – 8 °C, unopened reagents will retain reactivity until expiration date. Do not use reagents beyond this date.

  • Microtiter Plate: Wells coated with anti testosterone antibody.
  • Calibrators (6 vials): Concentration 0, 0.2, 1.0, 4.0, 20.0, 100.0 pg/ml, made up from testosterone.
  • Control: Containing anti human free testosterone (concentration is lot-specific).
  • Enzyme Conjugate: Consisting of testosterone conjugated to horseradish peroxidase (HRP).
  • TMB Substrate.
  • Stop Solution.
  • Wash Solution (10x Concentrated).


The minimum sensitivity detection limit of human unbound or free testosterone using current free testosterone ELISA kit was approximately 0.06 pg/ml. The dynamic range for this assay is 0.2 – 100.0 pg/ml.


– Sensitivity: 0.06 ng/ml
– Intra-Assay Variation: The within assay variability is ≤ 10%.
– Inter-Assay Variation: The between assay variability is ≤ 10%.
– Specificity (Cross Reactivity): Testosterone (100%), Androstenedione (0.0043%), Androsterone (0.00029%), DHT (0.00008%), DHEA-S (0.00007%), 17β Estradiol (0.00005%), Cortisol, Cortisone, Estrone, Prednisone, 17α Ethynilestradiol, Norgestrel, Danazol, Aldosterone, Sodium Citrate, EDTA, Heparin (< 0,00001%).
– Reference Values: Male (4.5 – 42 pg/ml), Female (ovulating ND – 4.1 pg/ml, oral contraction 0.3 – 2.0 pg/ml, post-menopausal 0.1 – 1.7 pg/ml).


  1. Free testosterone: clinical utility and important analytical aspects of measurement. Adv Clin Chem. (2014) 63: 59-84. Review. Shea J.L., et al.
  2. Obesity, low-testosterone levels and erectile dysfunction. Int J Impot Res. (2009) 21 (2): 89-98. Review. Diaz-Arjonilla M., et al.
  3. A critical appraisal of accuracy and cost of laboratory methodologies for the diagnosis of hypogonadism: the role of free testosterone assays. Can J Urol. (2012) 19 (3): 6314-8. Review. Morales A., et al.
  4. Principles and pitfalls of free hormone measurements. Best Pract Res Clin Endocrinol Metab. (2013) 27 (5): 631-45. Review. Faix JD.


  • Full Name: Free Testosterone ELISA Kit
  • Reactivity: Human
  • Sample Type: Serum, Plasma
  • Sensitivity: 0.04 pg/ml



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