It’s true that endogenous (natural) testosterone levels decline both with age and for a variety of other reasons, however many of the symptoms that lead to a diagnosis of low testosterone can occur so gradually that they may go unnoticed and/or appear nonspecific making them somewhat difficult to identify.  Although the history of symptoms (past and present) are an important measure, a physician often employs and cross references a variety of existing methods to accurately arrive at a diagnosis of low testosterone.  This multi-faceted approach to identifying low testosterone greatly reduces the odds of misinterpreted symptoms, which can lead to misdiagnoses and to the unnecessary prescribing of testosterone therapies.  The primary methods for determining low testosterone are outlined below, and when applied together can conclusively refute or determine the condition of low testosterone.

Low Testosterone History of Symptoms 

The self-report is probably the most prevalent initiator, i.e., the factor/measure that brings this condition into question among adult males.  The majority of men seek medical treatment for low testosterone levels due to a perceived decrease in libido (sex drive), or an often noticeable reduction in their sexual performance, i.e., erectile dysfunction – the chronic inability to achieve or maintain an erection for satisfactory intercourse.  Although testosterone is largely responsible for regulating the libido and facilitating the male reproductive system, it is also integral to maintaining the body’s general balance and overall well-being.  Secondary reasons for which men seek testosterone testing include feelings of excessive fatigue, muscular weakness, and depression all of which are common symptoms of a decline in testosterone secretion.

A low testosterone level (often cited as being below 300 ng/dL) can manifest itself as a variety of health-related conditions.  In fact, the hormone testosterone is so influential in maintaining balance within the male body that when levels drop below normal other bodily systems can be seriously impacted.  For example, in addition to the earlier mentioned sexual dysfunctions, low testosterone can:  affect the brain’s faculties manifesting as emotional disturbances, mental instability, and memory complications; disrupt sleep patterns; reduce energy levels; promote body fat gain; decrease one’s ability to cope with traditional life’s stressors; etc.

The standard self-reporting assessment tool for measuring low testosterone is a simple 10-question test known as the ADAM (Androgen Deficiency in Aging Men) Questionnaire, which queries the tester in a variety of areas that are directly and indirectly related to testosterone levels.  This ‘yes’ or ‘no’ answered questionnaire addresses quality of life (work and play), sexuality, mood, energy, stature, and sleep, and is best employed as preliminary tool for identifying low testosterone.  The ADAM questionnaire is quick and easy way to provide physicians with a starting point for identifying low testosterone, and its questions are as follows:

Generally while compiling a history of symptoms, the physician will collect other pertinent historical information if it’s not already on file.  Such information includes personal medical, sexual, and family medical histories.  Prior to the appointment, it is helpful to compile a list of parents, siblings, aunts, uncles, and grandparents, along with any applicable causes of death and ages at the time of death.  Additionally, for close relatives with known conditions who are still alive, it would be wise to secure their present ages.  This information will help the physician identify potential genetic traits and tendencies.  Examples of historical profiles would look similar to these:

PERSONAL HISTORY

• Blood Type
• Allergies
• Previous and existing conditions; major and chronic illnesses
• All prescription and non-prescription drugs currently being taken
• Dates and reasons for previous medical visits
• Dates and kinds of surgeries
• Dates of immunizations
• Names of current and previous doctors
• Copies of past test results
• Lifestyle habits – smoking, alcohol consumption, binge eating, etc.
• Family and relationship problems, including any sexual ones
• Major life events or changes

FAMILY HISTORY

• Alcoholism
• Mental illness
• Kidney disease
• Diabetes
• Blood diseases (hemophilia or sickle cell)
• Cancer (all types)
• Other illnesses and disorders

SEXUAL HISTORY

• Any genital abnormalities present from birth
• When and how quickly puberty took place
• Number of nocturnal emissions
• Current status of sexual function such as frequency of intercourse and masturbation
• Degree of penile rigidity during erections
• Frequency of sexual thoughts, desires, and fantasies
• Changes in the status of secondary sexual characteristics such as hair growth throughout the body, muscular strength, and energy level

Low Testosterone Physical Examination

Testosterone is a central component in primary male development, a low testosterone diagnosis within the pediatric age group is generally sought after the parent or health care professional discovers abnormalities or notices delays in physical development, e.g. undescended (retained within the iliac region rather than descending into the scrotum) testicles, low body weight, shortened stature (height), etc.  Men however, tend to experience either steady or pronounced changes within the body such as:

• Increased body fat
• Reduction in muscle and/or bone mass
• Changes in the amount of body hair
• Changes in the size of, or lumps in the breasts, testes, scrotum, and penis
• Difficulty sleeping
• Loss of peripheral vision often indicates the presence of a pituitary tumor, which can cause low testosterone levels

The physical exam typically contains a variety of additional questions about the patient’s current condition, that are not physically visible and are differentiated from past medical history questions.  Such questions are generally similar to, but probe deeper than questions found on the ADAM Questionnaire, and center around traditional hypogonadic symptoms such as:

• Depression, anxiety, irritability
• Excessive sweating and night sweats
• Loss of body, facial and pubic hair
• Increased breast tissue (gynecomastia)
• Poor concentration and/or memory
• Insulin resistance
• Recent bone fractures; loss of bone mass (osteoporosis)

Low Testosterone Blood Tests

Lastly, the patient advances to the blood test stage of identifying low testosterone.  Generally considered the ‘smoking gun’, and technically it is, blood tests vary (especially older ones), but a good test measures (from two samples) the total testosterone level, and then either measures or calculates via amounts of ‘free’ (available for function) and ‘bound’ (inactive) testosterone within the bloodstream.  This calculation is often based on the levels of a liver synthesized glycoprotein called sex hormone-binding globulin (SHBG) that binds with and disables circulating androgens and estrogens.

The level of testosterone varies depending upon the time of day, thus blood samples should be drawn between 8:00 and 9:00 AM when blood serum concentrations are highest.  Normal total testosterone levels range from 300 – 1,200 nanograms per deciliter (ng/dl).  Scores lower than 300 ng/dL (the lower limit) generally constitute a diagnosis of low testosterone.  Often a score within the lower range will in fact translate into hypogonadic symptoms, but not necessarily.  However, testosterone scores below the lower limit, for example 200 or 100 ng/dL, are always accompanied by such symptoms.

Based on the clinical situation, a physician may run further tests to determine whether the low testosterone is due to one of three basic conditions:  1) primary hypogonadism – originates from a problem in the testicles; 2) secondary hypogonadism – originates from a problem in the hypothalamus or the pituitary gland, the two parts of the brain that signal the testicles to produce testosterone; or 3) originates from another internal condition or an external stimulus.  A blood test is not merely used to assess lower than normal testosterone levels within the body, but can also be used to determine the possible cause(s).  For example, low testosterone can also be caused by thyroidal imbalances, as well as other non-hormone related conditions or disorders, such as:

• Obesity
• Infection
• Type 2 diabetes
• Injury to the testicles
• HIV/AIDS
• Hormonal disorders
• Chronic liver or kidney disease
• Testicular cancer or treatment of testicular cancer

More specifically, some of the tests used to identify non-hypogonadic underlying cause(s) of low testosterone include:

• Semen analysis
• Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) testing; LH and FSH are hormones released by the pituitary gland that normally stimulate testosterone production in males
• Chromosome or genetic testing, if a genetic condition is suspected
• Pituitary function testing, if the problem is suspected to occur in the pituitary gland
• A magnetic resonance imaging (MRI), if the problem is thought to occur in the pituitary gland or hypothalamus in the brain.
• Prolactin level testing, as high prolactin levels can cause low testosterone; prolactin is a hormone produced in the pituitary gland, so named because of its central role in lactation (producing breast milk), is a multi-faceted hormone found in males and females that is essential to immune system maintenance

Once the cause of low testosterone is determined and addressed in the appropriate clinical manner, testosterone levels are generally restored to normal without further action.  In the event that primary hypogonadism is the culprit, the most likely course of action is testosterone replacement therapy (TRT) – the use of synthetic testosterone for the treatment of hypogonadic symptoms in men, and secondarily for use in women.

REFERENCE LIST

• The quantitative ADAM questionnaire: a new tool in quantifying the severity of hypogonadism
• O Mohamed,¹ R E Freundlich,¹ H K Dakik,¹ E D Grober,² B Najari,³ L I Lipshultz,¹ and M Khera^1,*
• Int J Impot Res. 2010 January; 22(1): 20–24.
• Published online 2009 August 6. doi:  10.1038/ijir.2009.35
• Low Testosterone and How it is Diagnosed by Chris Steidle, MD
• Low testosterone or andropause can be complicated to diagnose. A list of symptoms of low testosterone that you share with your doctor can play a major role in helping both of you decide if testosterone replacement therapy should be considered.
• Moore C, Huebler D, Zimmermann T, Heinemann LA, Saad F, Thai DM. The Aging Males’ Symptoms scale (AMS) as outcome measure for treatment of androgen deficiency. Eur Urol. 2004;46:80–87. [PubMed]
• The Mayo Clinic
  Mayo Foundation for Medical Education and Research
• Male hypogonadism http://www.mayoclinic.com/health/male-hypogonadism/DS00300/DSECTION=causes
• O’Leary MP. Development of an index to evaluate symptoms in men with androgen deficiency. Rev Urol. 2003;5 Suppl 1:S11–S15. [PMC free article] [PubMed]