What lab monitoring is required for patients receiving testosterone (hormone replacement therapy) injections?

From the Guidelines

Laboratory monitoring for testosterone injections should include baseline testing before starting therapy, followed by regular monitoring at 3-6 month intervals during the first year, then annually thereafter, with a focus on measuring total testosterone, prostate-specific antigen (PSA) in men over 40, hematocrit, and lipid panels, as recommended by the American Urological Association guideline 1.

Key Components of Laboratory Monitoring

• Baseline testing should include total testosterone, luteinizing hormone (LH), follicle-stimulating hormone (FSH), complete blood count (CBC), liver function tests, lipid panel, PSA in men over 40, and hemoglobin A1c.
• During follow-up visits, testosterone levels should be checked to ensure they remain in the therapeutic range (typically 400-700 ng/dL), with blood draws occurring midway between injections for accurate assessment 1.
• Hematocrit requires careful monitoring as testosterone therapy commonly increases red blood cell production, with levels above 54% warranting dose adjustment or therapeutic phlebotomy to prevent blood viscosity complications.
• Liver function tests help detect potential hepatotoxicity, while lipid panels monitor cardiovascular risk factors as testosterone may affect cholesterol levels.
• For older men, PSA monitoring is essential to detect potential prostate issues, with a digital rectal examination and PSA measurement recommended at baseline and during follow-up visits 1.

Adjusting Therapy Based on Laboratory Results

• Adjustments to dosing frequency or amount may be necessary based on both laboratory values and symptom response.
• If the patient reports an adequate clinical response to testosterone supplementation, there is no need for dosage adjustment, even if levels are in the low-normal range.
• If the clinical response is suboptimal and testosterone levels are no higher than the low-normal range, the testosterone dosage should be increased.
• If the hematocrit rises above the reference range, consideration should be given to temporarily withholding testosterone-replacement therapy, reducing the dosage, or performing phlebotomy 1.

From the FDA Drug Label

Laboratory tests: Hemoglobin and hematocrit levels (to detect polycythemia) should be checked periodically in patients receiving long-term androgen administration. Serum cholesterol may increase during androgen therapy. The recommended lab monitoring for patients receiving testosterone injections includes:

• Hemoglobin and hematocrit levels to detect polycythemia
• Serum cholesterol levels to monitor for potential increases during androgen therapy 2

From the Research

Lab Monitoring for Testosterone Injections

• Regular laboratory monitoring is recommended for patients undergoing testosterone replacement therapy (TRT) to check for adverse effects such as polycythemia 3.
• The Canadian guidelines suggest discontinuing TRT or reducing the dose if the hematocrit exceeds 54% (hemoglobin ≥180 g/L) 3.
• Studies have shown that hemoglobin concentrations can be elevated in patients on TRT, with significant numbers having hemoglobin levels above the recommended threshold 3, 4.
• Lab monitoring should include measurement of serum testosterone levels, hematocrit, and prostate-specific antigen (PSA) levels, especially in men over 50 years old 5.
• Providers should decrease or discontinue testosterone therapy if the patient's hematocrit exceeds 54% until the hematocrit normalizes 4.
• The use of testosterone therapy in men with a history of prostate cancer is still controversial, and requires thorough clinical evaluation and close monitoring 6, 7.