Testosterone Level Monitoring Schedule During Replacement Therapy
Testosterone levels should be checked at 2-3 months after initiating therapy or any dose change, then at 3-6 month intervals during the first year, followed by annual monitoring thereafter. 1
Initial Monitoring Phase
First Follow-Up Visit
- Schedule the first follow-up at 1-2 months after starting testosterone replacement therapy to assess treatment response and consider dose adjustments 1
- Perform formal testosterone level testing at 2-3 months after treatment initiation or after any dose change 1
Timing Considerations for Blood Draw
- For injectable testosterone (cypionate or enanthate), measure levels midway between injections (typically day 5-7 for weekly injections) to accurately assess treatment efficacy 1
- Peak serum testosterone occurs 2-5 days post-injection, with return to baseline by 10-14 days, creating fluctuating levels that must be considered when interpreting results 1
- For transdermal gel formulations, FDA labeling recommends checking pre-dose morning testosterone concentration at approximately 14 days and 28 days after starting treatment or following dose adjustment 2
Ongoing Monitoring Schedule
First Year
- Monitor at 3-6 month intervals throughout the first year of therapy 1
- The FDA recommends re-evaluation at 3 months after testosterone initiation for patients on transdermal preparations 2
Long-Term Monitoring
- After the first year, perform monitoring at least annually 1, 3, 4
- Continue monitoring for as long as treatment continues, with frequency adjusted based on clinical response and stability 4
Comprehensive Monitoring Parameters Beyond Testosterone
At Each Visit, Assess:
- Serum testosterone levels (target mid-to-upper normal range) 1
- PSA levels to detect prostate-related issues 1
- Hematocrit or hemoglobin (if hematocrit rises above reference range, consider temporarily withholding therapy, reducing dose, or performing phlebotomy) 1
- Symptomatic response to treatment, voiding symptoms, and sleep apnea 1
- Physical examination including digital rectal examination 1
PSA Monitoring Thresholds Requiring Action:
- Perform prostate biopsy or refer to urology if PSA rises above 4.0 ng/mL 1
- Consider biopsy if PSA increases by 1.0 ng/mL or more within any 12-month period 1
- If PSA rises by 0.7-0.9 ng/mL in one year, repeat PSA in 3-6 months and perform biopsy if further elevation occurs 1
- A PSA increase of more than 0.4 ng/mL per year after the first 6 months of treatment warrants urologic referral 1
Common Pitfalls to Avoid
- Do not measure testosterone during GnRH agonist recovery: After discontinuation of GnRH agonists, testosterone may not return to normal for a median of 16.6 weeks; avoid measuring during this period 1
- Timing matters for injectable formulations: Measuring at peak (2-5 days post-injection) versus trough (10-14 days) will yield dramatically different results; standardize timing at midpoint 1
- Use consistent laboratory methods: All PSA values should be obtained using the same assay, preferably at the same laboratory, to ensure accurate trend monitoring 1
- Account for formulation differences: Transdermal gels produce different pharmacokinetic profiles than injectables; timing of blood draws must be adjusted accordingly 5