How often should testosterone levels be checked in a man with erectile dysfunction?

Testosterone Monitoring in Men with Erectile Dysfunction

Testosterone levels should be measured in all men with erectile dysfunction at initial diagnosis, followed by monitoring at 3-6 months after initiating treatment, and then annually thereafter if on testosterone replacement therapy.

Initial Assessment

When evaluating men with erectile dysfunction (ED), testosterone measurement is a critical component of the diagnostic workup:

• The Princeton III Consensus recommends that testosterone levels be measured in all men with a diagnosis of organic ED, especially in those for whom PDE5 inhibitor therapy has failed 1
• The American Urological Association (AUA) guidelines explicitly state: "In men with ED, morning serum total testosterone levels should be measured" (Moderate Recommendation; Evidence Level: Grade C) 1
• Measurement should be done in the early morning when testosterone levels are highest

Diagnostic Criteria

• A total testosterone level below 300 ng/dL is considered a reasonable cut-off to support the diagnosis of low testosterone 1
• The diagnosis of testosterone deficiency requires at least two separate morning measurements showing low levels 1
• Clinical diagnosis should only be made when low testosterone levels are combined with symptoms and/or signs of deficiency 1

Monitoring Schedule

For men diagnosed with ED who are started on testosterone replacement therapy (TRT):

1. Initial follow-up: Check testosterone levels at 3-6 months after starting therapy 2
2. Long-term monitoring: Annual testosterone level measurement 2
3. Additional monitoring parameters:
   • Hematocrit (discontinue therapy if exceeds 54%)
   • PSA (in men ≥40 years)
   • Symptom evaluation

Target Levels and Action Thresholds

Parameter	Target Range	Action Threshold
Total Testosterone	450-600 ng/dL	Adjust dose if outside target range
PSA	N/A	Consider biopsy if >4.0 ng/mL or increases >1.0 ng/mL/year
Hematocrit	<54%	Discontinue therapy if exceeds 54%

Special Considerations

Non-responders to PDE5 Inhibitors

• Hypogonadism is a potential cause of lack of response to PDE5 inhibitor therapy 1
• In men who fail to respond to PDE5 inhibitors alone, combined treatment with testosterone plus PDE5 inhibitors may be effective 3, 4
• One study found that all hypogonadal men who failed testosterone therapy alone responded positively when sildenafil was added to their treatment regimen 4

Cardiovascular Risk Assessment

• ED is a risk marker for underlying cardiovascular disease 1
• Low testosterone levels have been associated with increased all-cause and cardiovascular mortality in multiple studies 1
• Men with ED should undergo cardiovascular risk assessment regardless of testosterone status

Fertility Considerations

• Men with desire for current or future fertility should not use TRT as it suppresses spermatogenesis 2
• Alternative approaches such as human chorionic gonadotropin (hCG) injections can be considered for men with hypogonadism who wish to preserve fertility 2

Common Pitfalls to Avoid

1. Single measurements: Relying on a single testosterone measurement is insufficient; at least two separate morning measurements are required 1, 2

2. Ignoring symptoms: Testosterone deficiency should only be diagnosed when low levels are combined with symptoms/signs 1

3. Inadequate monitoring: Failing to monitor testosterone levels after initiating therapy (studies show nearly half of men on TRT do not have their levels checked) 1

4. Overlooking cardiovascular risk: ED is a marker for cardiovascular disease risk that warrants evaluation regardless of testosterone status 1

5. Missing hypogonadism in ED patients: Studies suggest that 15-36% of men with ED have hypogonadism 1, 5, making testosterone measurement essential

By following these guidelines for testosterone monitoring in men with ED, clinicians can optimize treatment outcomes while minimizing potential risks associated with testosterone therapy.