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Distance: 25 KM
Actual Price: $22.00
Price: $22.00

Testosterone Free

Also known as

Free T-Index, Free Testosterone

The test is taken to identify atypical testosterone levels in males and females. In females, excess testosterone can trigger excess body hair (hirsutism), infertility, polycystic ovary syndrome (PCOS), or masculine physical features (virilization). In males, it can lead to erectile dysfunction or the inability to impregnate a partner (infertility). In children, the test helps identify the reason for early or late puberty or the reason for genitals that are neither male nor female (ambiguous genitalia). The test is taken to track testosterone levels in transgender individuals undergoing hormone therapy.
A blood sample is drawn from a vein in the arm.
There is no preparation needed for the test.
Lower than 4% of the total testosterone in the body circulates the blood as free testosterone. Free testosterone and testosterone bound to albumin can act on target tissues. This is called bioavailable testosterone. The hormone is found in both males and females but is the primary sex hormone (androgen) in males. Women have a much lower level of testosterone level in comparison to men. Testosterone is produced primarily by testicles in males, but it is also made by the adrenal glands of both females and males. Ovaries in women also produce minute quantities of testosterone. The hormone prompts the development of secondary sex characteristics like body hair growth, muscle development, deepening of the voice, and enlargement of the penis in males. Testosterone levels are high during puberty and adulthood in males as it controls sex drive and helps sustain muscle mass. Testosterone is changed to estradiol, a sex hormone in women. The production of testosterone is regulated by the Luteinizing Hormone (LH), which is made by the pituitary gland. Testosterone works within a negative feedback loop. This means that lower levels of testosterone lead to high LH, which triggers the production of testosterone while an increase in testosterone levels leads to a decrease in the production of LH, which leads to a reduction in testosterone production. Testosterone levels are diurnal. It is present in its highest concentration in the morning, between 4:00 to 8:00 am, and lowest concentration in the evening, between 4:00 to 8:00 pm. Testosterone levels lower with age and increase with exercise. Two-thirds of testosterone in the body is bound to the protein sex hormone-binding globulin (SHBG), while one-third is bound to the protein albumin, which is in high levels in the bloodstream.
The testosterone test is often used with other hormone level tests to assess the following issues:
  • Delayed puberty in boys
  • Precocious (early) puberty in boys
  • Decreased sex drive in males and females
  • Erectile dysfunction in males
  • Infertility in males and females
  • Testicular tumors in males
  • Hypothalamus or pituitary disorders
  • Development of male physical characteristics such as excess facial and body hair (hirsutism) in girls and women
  • Genitals that are not male or female (ambiguous genitalia) in infants
  • Testosterone testing is also used to track testosterone levels in transgender individuals undergoing hormone therapy.
  • The test is requested by doctors for men when they have decreased libido, erectile dysfunction, or in cases of infertility. Men with lower levels of testosterone may have no beard and body hair, small testicles, decreased muscle mass, and development of breast tissue (gynecomastia). Boys generally reach puberty between the ages of 9 and 14. In cases of early or late puberty, Testosterone Total Blood Test is ordered alongside FSH and LH blood tests. It is also requested if the following signs and symptoms are observed:
  • Increase in muscle mass
  • Deepening of the voice
  • Growth of body hair and pubic hair
  • Growth of testicles and penis
  • The test is taken for women in case of irregular or absent periods known as amenorrhea, difficulty getting pregnant, or development of masculine characteristics, for example, excess facial and body hair, male pattern baldness, and/or a low voice. In infants, the test is taken in cases where the genitals are not male or female (ambiguous genitalia)
    Testosterone levels vary with age and stage of maturity in males, and the normal range also varies widely. After age 30, testosterone levels normally begin reducing steadily in males. Low testosterone levels (male hypogonadism) maybe because of:
  • Chronic diseases such as type 2 diabetes, HIV, liver disease, kidney disease, or autoimmune diseases
  • Physical injury or trauma to the testicles
  • Viral diseases like mumps
  • Chemotherapy or radiation therapy
  • Removal of testicles to treat cancer
  • Use of medications such as antidepressants or narcotic pain medications
  • Hypothalamic or pituitary disease
  • Genetic diseases that can cause decreased testosterone production in young men (e.g., Klinefelter, Kallman, and Prader-Willi syndromes) or testicular failure and infertility (e.g., myotonic dystrophy, a form of muscular dystrophy)
  • Increased testosterone levels in males suggest:
  • Testicular tumors
  • Adrenal tumors that are producing testosterone
  • Use of anabolic steroids, which contain synthetic testosterone
  • Early puberty of unknown cause in boys
  • Congenital adrenal hyperplasia in babies and children
  • In Females: Women generally have low levels of testosterone in comparison to men, and the normal range for women also varies from that of men. High testosterone levels can suggest the following :
  • Polycystic ovary syndrome (PCOS)
  • Ovarian tumor or adrenal gland tumor
  • Congenital adrenal hyperplasia
  • Testosterone exposure from physical contact with someone around them using topical testosterone products
  • Related Tests

    Follicle-stimulating Hormone (FSH), Luteinizing Hormone , (LH), Sex Hormone Binding Globulin (SHBG), DHEAS, Estrogens, Semen Analysis, Anti-Müllerian Hormone, Androstenedione