When should adult male testosterone levels be checked?

Reasons to Check Adult Male Testosterone Levels

Testosterone testing in adult men should be performed when there are specific symptoms of hypogonadism, particularly sexual dysfunction, along with risk factors for low testosterone, rather than as a routine screening test. 1

Primary Indications for Testing

Sexual Symptoms

• Decreased libido/sex drive - One of the most reliable symptoms associated with low testosterone 1, 2
• Erectile dysfunction - Though this may have multiple causes, it's a common symptom of hypogonadism 1
• Decreased volume of ejaculate 1
• Reduced morning erections 1

Physical Signs and Symptoms

• Loss of body and facial hair 1
• Decreased muscle mass 1
• Increased body fat/obesity 3
• Decreased bone mineral density/osteoporosis 1, 4, 3
• Gynecomastia (breast development in men) 5

Metabolic and Systemic Conditions

• Type 2 diabetes - Particularly with poor glycemic control (HbA1c >6%, fasting glucose ≥100 mg/dL) 1, 2
• Chronic systemic illness - Including COPD, chronic kidney disease, HIV, etc. 4, 3
• Delayed puberty or eunuchism - For diagnosis and treatment planning 5

Testing Protocol

When to Test

• Morning testing is essential - Testosterone should be measured between 7 AM and 12 PM when levels are highest 3
• Multiple measurements required - At least two separate morning measurements on different days 5
• Age-appropriate reference ranges - Different cutoffs should be considered based on age groups:
  • Ages 20-24: <409 ng/dL
  • Ages 25-29: <413 ng/dL
  • Ages 30-34: <359 ng/dL
  • Ages 35-39: <352 ng/dL
  • Ages 40-44: <350 ng/dL
  • Older adults: <300 ng/dL 6

Common Pitfalls in Testing

1. Inappropriate timing of blood draws - Only 9% of testosterone tests are performed during the recommended morning hours 3
2. Single measurements - Relying on a single test rather than confirming with a second test 5
3. Testing based on non-specific symptoms alone - Symptoms like fatigue and depression often don't correlate with testosterone levels 2
4. Using age-inappropriate reference ranges - Using the same cutoff (300 ng/dL) for all ages despite natural age-related decline 6
5. Failure to rule out secondary causes - Not investigating other causes of hypogonadism before diagnosing age-related low testosterone 1

Clinical Decision Algorithm

1. Identify patients with specific symptoms and risk factors:

   • Focus on sexual symptoms (decreased libido, erectile dysfunction)
   • Consider metabolic risk factors (diabetes, obesity)
   • Evaluate for bone health concerns (osteoporosis)

2. Perform proper testing:

   • Morning blood draw (7 AM - 12 PM)
   • Total testosterone measurement
   • Repeat on a separate day if initial result is low

3. Apply age-appropriate reference ranges to interpret results

4. Rule out secondary causes of hypogonadism before diagnosing age-related low testosterone

5. Consider treatment only for symptomatic patients with confirmed low testosterone, particularly those with sexual dysfunction 1

Important Considerations

• Testing rates have increased significantly in recent years, partly due to direct-to-consumer advertising 3
• Low testosterone is associated with increased morbidity and mortality in some studies 7
• Testosterone replacement therapy should be considered primarily for sexual function improvement, not for energy, vitality, physical function, or cognition 1
• The prevalence of low testosterone increases with age: approximately 20% in men over 60,30% in those over 70, and 50% in those over 80 years 1

By following these evidence-based guidelines for testosterone testing, clinicians can ensure appropriate diagnosis and management of hypogonadism while avoiding unnecessary testing and treatment.