When is a Testosterone Total test ordered?
A Testosterone Total test may be ordered in the following situations:
- Evaluation of Symptoms: The test may be ordered when individuals, regardless of gender, present with symptoms associated with testosterone deficiency or excess. Common symptoms in males include low libido, erectile dysfunction, fatigue, depression, and decreased muscle mass. In females, symptoms may include irregular menstrual cycles, infertility, and signs of virilization (excessive facial or body hair).
- Assessment of Hormonal Imbalances: The test can help diagnose and monitor conditions related to hormone imbalances, such as hypogonadism (low testosterone production), hypergonadism (excess testosterone production), or polycystic ovary syndrome (PCOS) in females.
- Monitoring Hormone Replacement Therapy: For individuals receiving testosterone replacement therapy or hormonal interventions, periodic testing of testosterone levels helps ensure appropriate dosing and monitor treatment effectiveness.
What does a Testosterone Total blood test check for?
n men, testosterone is the primary sex hormone. It’s in charge of a man’s physical appearance. Although it is thought to be a “masculine” sex hormone, it is found in both men and women’s blood. This test determines the amount of testosterone in a person’s blood.
Testosterone is primarily produced in the male testicles by unique endocrine tissue called Leydig cells. It’s also made by the adrenal glands in both males and females, as well as the ovaries in females in modest amounts.
In males, testosterone promotes the formation of secondary sex characteristics such as penis size, body hair growth, muscle development, and a deeper voice. It is abundant in males during adolescence and adulthood in order to regulate sex drive and preserve muscle mass. Estradiol is the major sex hormone in females, and testosterone is converted to it in women.
The pituitary gland produces luteinizing hormone, which stimulates and regulates testosterone synthesis. Testosterone functions in a negative feedback loop: when testosterone levels rise, LH production falls, slowing testosterone production; lower testosterone levels cause higher LH production, which promotes testosterone production.
Testosterone levels fluctuate throughout the day, increasing in the early morning hours and dropping in the evening. Levels rise after activity and fall as people get older.
About two-thirds of testosterone is attached to sex-hormone binding globulin in the bloodstream, with the remaining one-third bound to albumin. Only a small percentage of testosterone is released into the bloodstream as free testosterone. The bioavailable fraction is the free plus albumin-bound testosterone, which can act on target tissues.
In many circumstances, measuring total testosterone is sufficient information for a healthcare provider. A test for free or bioavailable testosterone may be performed in some circumstances, such as when the level of SHBG is abnormal, as it may more accurately indicate the presence of a medical issue.
