Testosterone levels Lab Investigations –Who Needs It?
It is a well-known fact that testosterone levels tend to decline with advancing age, yet in most cases, these changes are gradual and insignificant. It is also imperative to mention that even young adults can develops hypogonadism due to endocrinological issues and other systemic ailments. In poorly managed cases, its deficiency can aggravate the risk of morbidity and mortality in men. Healthcare professionals therefore advise testosterone lab investigations to ascertain if a person is experiencing abnormal symptoms due to hypogonadism.
Why Is It Important To Diagnose Hypogonadism?
Timely diagnosis and prompt management of low testosterone levels is important for a number of reasons. For example, besides compromising your fertility and sex life, hypogonadism can also make you more vulnerable to a number of organic and metabolic health issues such as cardiovascular dysfunction, musculoskeletal issues, obesity, diabetes, mental health problems (such as depression, anxiety, mood disorders and accelerated brain aging), to list a few (2). Also early identification of hypogonadism can help in the determination of other serious diseases that may present as hypogonadism.
Primary indications for which doctors usually advise testosterone levels in males are:
- Unexplained fertility
- Erectile dysfunction
- Disorders of hypothalamus/ pituitary gland
- Low sex drive
- Suspicion of testicular malignancy
Testosterone assessment is also advised in women on certain occasions; such as:
- Fertility issues
- If a woman is developing masculine characteristics such as deepening of voice, growth of facial hair etc.
- To rule out polycystic ovarian syndrome (PCOS)
- Menstrual irregularities or secondary amenorrhea
- Abnormal uterine bleeding
Assessment of serum testosterone levels is also advised in children on certain occasion such as:
- Ambiguous or malformed external genitalia at birth
- Premature or delayed puberty. Delayed puberty is marked by absence (or slow) growth of penis and testicles, lack of secondary sexual characteristics etc.
What Should You Know About Testosterone Assessment?
Serum testosterone levels follow a diurnal pattern i.e. serum levels are generally low in the evening hours and peak early in the morning (4:00 am to 8:00 am). In addition, your serum levels rises after physical activity and exercise as well. Serum testosterone levels are measured by collecting a blood sample from forearm. Experts recommend that testosterone levels are generally high in the morning, which is why blood sample should be ideally drawn in the early morning hours from the forearm.
The hormone testosterone is mainly secreted from the testicles as well as some other glands and tissues (such as adrenal gland). The secretion is controlled by higher brain centers such as pituitary and hypothalamus via variety of secretory and inhibitory hormones such as luteinizing hormone (LH). Most of the secreted hormone is in the bound form and is therefore unavailable for biological use. Sex-hormone binding globulin (SHBG) bounds 2/3rd of the total testosterone, while slightly less than 1/3rd of the testosterone is bound to albumins. Only about 4% of the secreted testosterone circulates freely in the blood.
The testosterone assessment test calculates free as well as bound testosterone in order to obtain total testosterone concentration. The findings help in establishing important inferences; such as:
- Whether the person has normal/abnormal testosterone levels.
- Whether the cause of abnormal testosterone levels is central (higher brain centers) or peripheral (such as abnormal SHBG).
What Are Some Other Tests That Are Usually Advised With Testosterone Levels?
Depending upon the indications, presentation and symptoms, following tests are often advised in conjunction with testosterone levels:
- SHBG (steroid hormone binding globulin)
- FSH (follicular stimulating hormone)
- LH (Luteinizing hormone)
- Dehydroepiandrosterone sulfate
1. ANSONG, K. S., & PUNWANEY, R. B. (1999). An assessment of the clinical relevance of serum testosterone level determination in the evaluation of men with low sexual drive. The Journal of urology, 162(3), 719-721.
2. Muraleedharan, V., Marsh, H., Kapoor, D., Channer, K. S., & Jones, T. H. (2013). Testosterone deficiency is associated with increased risk of mortality and testosterone replacement improves survival in men with type 2 diabetes. European Journal of Endocrinology, 169(6), 725-733.
3. Schüring, A. N., Nolte, S., Fobker, M., Kannenberg, F., & Nofer, J. R. (2015). Head‐To‐Head Assessment of Diagnostic Performance of Testosterone Immunoassays in Patients With Polycystic Ovary Syndrome. Journal of clinical laboratory analysis.