What labs are monitored during testosterone therapy?

Laboratory Monitoring for Testosterone Therapy

During testosterone replacement therapy, clinicians should monitor total testosterone levels, hemoglobin/hematocrit, PSA (in men over 40), and assess cardiovascular risk factors to minimize risks and ensure treatment efficacy. 1

Initial Laboratory Assessment (Before Starting Therapy)

• Total Testosterone: Confirms diagnosis of testosterone deficiency
• Luteinizing Hormone (LH): Helps establish etiology (primary vs. secondary hypogonadism)
• Hemoglobin/Hematocrit: Baseline measurement to monitor for polycythemia
• Prostate-Specific Antigen (PSA): For men over 40 years
• Cardiovascular Risk Assessment: Evaluates fixed and modifiable risk factors

Additional Initial Testing When Indicated

• Prolactin: Required when total testosterone is low with low/low-normal LH levels
• Estradiol: Measure in patients presenting with breast symptoms or gynecomastia
• Follicle-Stimulating Hormone (FSH): For men interested in preserving fertility
• Lipid Profile: For cardiovascular risk assessment

Ongoing Monitoring Schedule

1. Testosterone Levels:

   • First check: 2-3 months after treatment initiation or dose change
   • Ongoing: Every 6-12 months once stable 2, 1
   • Target: Mid-normal range (350-600 ng/dL)

2. Hemoglobin/Hematocrit:

   • First check: 1-2 months after initiation
   • Ongoing: Every 3-6 months during first year, then annually 1
   • Action threshold: Withhold therapy if hematocrit exceeds 50%; intervention warranted if exceeds 54% 1

3. PSA (men over 40):

   • Monitor according to standard prostate cancer screening guidelines
   • If elevated, a second test is recommended to rule out spurious elevation 1

4. Liver Function Tests:

   • Particularly important with oral testosterone formulations due to potential hepatotoxicity 3

Critical Monitoring Considerations

Polycythemia Management

• Most common adverse effect of testosterone therapy 4
• Risk varies by administration route:
  • Injectable testosterone: 43.8%
  • Transdermal patches: 15.4%
  • Gels: 2.8-17.9% (dose-dependent) 1
• If hematocrit exceeds 54%:
  1. Temporarily discontinue therapy until normalized
  2. Consider dose reduction when restarting
  3. Consider therapeutic phlebotomy if clinically indicated 1

Prostate Monitoring

• If two PSA levels raise suspicion for prostate cancer, consider:
  • Reflex testing (4K or phi)
  • Prostate biopsy with/without MRI 1
• Discontinue therapy if prostate cancer is detected 5

Sexual Function and Fertility

• Monitor for priapism or excessive sexual stimulation
• Be aware that oligospermia may occur after prolonged administration 5
• For men desiring fertility, consider alternative therapies such as aromatase inhibitors, human chorionic gonadotropin, or selective estrogen receptor modulators 2

Pitfalls to Avoid

1. Relying solely on blood donation to manage polycythemia: Studies show this is insufficient to maintain hematocrit below 54% in many patients 4

2. Ignoring cardiovascular risk: Testosterone therapy may increase risk of cardiovascular events, particularly in patients with pre-existing risk factors 1

3. Continuing ineffective therapy: Evaluate symptom improvement within 12 months and discontinue treatment if no improvement occurs 1

4. Using compounded testosterone: Commercially manufactured testosterone products should be prescribed rather than compounded testosterone due to variations in potency and quality 2

5. Overlooking drug interactions: Androgens may increase sensitivity to oral anticoagulants, requiring dose adjustments 5

By following this structured monitoring approach, clinicians can maximize the benefits of testosterone therapy while minimizing potential risks to patients.