Testosterone Deficiency Hypogonadism Diagnosis

Male hypogonadism occurs when the testes do not produce sufficient testosterone. However, because normal testosterone levels fluctuate based on a variety of factors, diagnosing a patient with a testosterone deficiency requires more than just measuring the level of testosterone in the blood. Physicians often consider what symptoms the patient is experiencing and how low testosterone may be contributing.

Physical Examination and Interview Regarding Hypogonadism Symptoms

A physician may suspect a male patient has hypogonadism based on assessment from a physical exam or interview. The following conditions are suggestive of hypogonadism:

  • A newborn baby with genitals that appear underdeveloped or ambiguous
  • A teenager with delayed puberty
  • An adult seeking treatment for erectile dysfunction or changes in mood or cognitive function.

The physician may also consider if there is any reason the patient would be at risk for low testosterone levels. For example, an undescended testicle in a young boy would be an additional reason to suspect hypogonadism. For adults, hypogonadism is especially common in men with high blood pressure or who are diabetic or obese.

Blood Test for Testosterone Levels

If your doctor suspects hypogonadism, the next step is a blood test to measure testosterone levels. Most laboratories measure total testosterone in the blood, but some can perform the test to measure free testosterone levels (testosterone that is not bound to any protein) and bioavailable testosterone (free testosterone plus testosterone bound to the protein albumin).

Different laboratories may use somewhat different guidelines for determining the normal range for total testosterone. In a young man, a measurement of 220 to 250 nanograms/deciliter (ng/dL) is considered low by most standards. A testosterone level between 250 and 350 ng/dL is often classified as borderline.

Because testosterone levels generally drop, often significantly, throughout the course of the day, the blood sample needs to taken in the morning to ensure consistent results.

Follow-Up Testing to Confirm a Hypogonadism Diagnosis

If the results of a blood test indicate that testosterone levels are low, the reason for the testosterone deficiency may need to be investigated. For example, in an infant or adolescent with hypogonadism, tests to measure the levels of pituitary hormones will help determine if the condition is due to improper signaling between the brain and the testes (a condition called “secondary hypogonadism”). For an older adult male, a hypogonadism diagnosis is often attributed to the natural decline in testosterone that occurs during aging and no further testing is conducted.

In some cases, testosterone replacement therapy may be prescribed to treat hypogonadism. Patients on this kind of therapy often need to have their testosterone levels monitored with regular blood tests to ensure the dosage of testosterone is appropriate.


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Kemp, S. (2009). Hypogonadism. Retrieved January 18, 2010 from the eMedicine Web site: http://emedicine.medscape.com/article/922038-overview.

Mayo Foundation for Medical Education and Research. (2008). Male hypogonadism. Retrieved January 17, 2010 from the Mayo Clinic Web site: http://www.mayoclinic.com/health/male-hypogonadism/DS00300/DSECTION=complications.

WebMD, LLC. (2008). Testosterone. Retrieved January 14, 2010 from the WebMD Web site: http://men.webmd.com/testosterone-15738.