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Hypogonadism and low testosterone in men

Get the insights you need to diagnose and manage male reproductive disorders

Prevalence of hypogonadism

Male hypogonadism is a clinical syndrome resulting from decreased testosterone and/or sperm production.1 It is estimated that 35% of men over 45 years of age have hypogonadism.2 There is a higher prevalence of hypogonadism in older men, obese men, and men with type 2 diabetes.2

Types and causes of hypogonadism

Hypogonadism can occur in 3 forms: primary, secondary, and combined. If initial and confirmatory testing indicates low testosterone, follicle stimulating hormone (FSH), and luteinizing hormone (LH) should be measured to distinguish between primary and secondary hypogonadism.1

When hypogonadism is diagnosed in men, additional diagnostic evaluation is recommended to determine the cause(s), which are classified as either organic or functional.

Organic causes include congenital, structural, or destructive disorders that suppress the hypothalamus, pituitary, or testis. Functional causes include conditions that suppress gonadotropins and testosterone concentrations, including diabetes, obesity, and the use of opioids.1

Diagnosing and managing hypogonadism

Laboratory testing is recommended for the diagnosis of men with suspected hypogonadism, especially when conditions associated with a high prevalence of low testosterone are present.1,3

Individuals suitable for testing

  • Men with symptoms, signs, or conditions associated with hypogonadism1,3
  • Men who are receiving testosterone replacement therapy (TRT)1,3

Symptom type3
Suggestive Nonspecific
Incomplete or delayed sexual developmenta

Loss of body hair

Very small testes (<6 mL)

Reduced libidoa

Decreased spontaneous erections

Erectile dysfunctiona


Eunuchoid body appearanceb

Inability to conceive, low sperm counta

Height loss

Osteoporosis or low-trauma bone fracturea

Low bone mineral density

Hot flashes, sweats

Decreased energy, motivation, initiative, self-confidence


Poor concentration and memory

Sleep disturbances

Mild unexplained anemia (normochromatic, normocytic)

Reduced muscle bulk and strength

Increased body fat, BMI

BMI, body mass index.
aHigh-prevalence conditions of low testosterone for which serum testosterone measurements are suggested.1
bEunuchoid body appearance is typical of hypogonadism occurring before epiphyseal fusion.

Conditions associated with decreased SHBG1 
Insulin resistance
Diabetes mellitus
Use of glucorticoids, some progestins, and androgenic steroids
Nephrotic syndrome
Polymorphisms in the SHBG gene


Conditions associated with increased SHBG1 
HIV disease
Cirrhosis and hepatitis
Use of some anticonvulsants
Use of estrogens
Polymorphisms in the SHBG gene


Identify hypogonadism with our testing strategy

Our adult male hypogonadism diagnostic algorithm provides a testing strategy for the diagnosis and classification of hypogonadism in men.

Guideline-supported testing recommendations

Initial diagnostic testing for low testosterone involves measuring morning fasting total testosterone (TT)1 by Liquid Chromatography, tandem mass spectrometry (LC-MS/MS), which is advantageous because:

  • LC-MS/MS provides a more precise and accurate measurement of TT at lower concentrations than immunoassay
  • LC-MS/MS is the recommended assay in the Endocrine Society guidelines1

Quest Diagnostics offers a Total Testosterone LC-MS/MS assay that is certified by the CDC Laboratory/Manufacturer Hormone Standardization (HoSt) Program, which is the Endocrine Society–recommended assay for healthy men older than age 18.1,4

Measurement of free testosterone (FT) is guideline-indicated if TT is reported near the lower limit of normal or if alterations in SHBG that affect TT are suspected.1 Guidelines recommend measuring FT by LC-MS/MS and an equilibrium dialysis method.1 The Endocrine Society recommends to confirm a low testosterone value with a second 8 AM measurement, and to initiate early treatment if both values are below normal.

Test name Test code
Testosterone, Total, MS 15983
Testosterone, Free (Dialysis) and Total, MS 36170

Monitoring patients with hypogonadism during testosterone therapy

The Endocrine Society recommends:

  • Testosterone therapy in hypogonadal men to induce and maintain secondary sex characteristics and correct symptoms of testosterone deficiency1 
  • Monitoring testosterone, hematocrit, prostate-specific antigen (PSA), and measurement of bone mineral density (BMD) for men who have started testosterone therapy1

Quest Diagnostics offers several tests to help you monitor patients undergoing testosterone therapy, including:

Test name
Test code
Hematocrit 509
PSA, Total 5363
Testosterone, Total, MS 15983

Get the answers you need to support care pathways for patients with hypogonadism

Explore the common symptoms of hypogonadism, guideline-recommended testing options to help inform a diagnosis, and recommended testing options for patients on testosterone therapy.




  1. Bhasin S, Brito JP, Cunningham GR, et al. Testosterone therapy in men with hypogonadism: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2018;103(5):1715-1744. doi:10.1210/jc.2018-0022e
  2. Endocrine Society. Hypogonadism in men. January 24, 2022. Accessed February 8, 2024.
  3. Bhasin S, Cunningham GR, Hayes FJ, et al. Testosterone therapy in men with androgen deficiency syndromes: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2010;95(6):2536-2559. doi:10.1210/jc.2009-235a
  4. Centers for Disease Control and Prevention. HoSt/VDSCP certified participants. Testosterone in serum; 2023. Accessed April 4, 2024.



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