Labs (Blood Tests) for TRT – 12 Rules to Live by on Testosterone
Timeline
Video Summary
Laboratory planning begins by separating baseline evaluation from ongoing monitoring during testosterone therapy. Baseline testing is framed as essential before any androgen exposure begins for the first time. Core primary care labs include a complete blood count and a fasting metabolic panel for kidney and liver function. Hemoglobin A1c and a lipid panel are highlighted to quantify diabetes risk and cardiovascular risk. Prostate screening starts with a total PSA, because prostate safety is treated as a central priority. Thyroid screening with TSH and reflex free T4 is suggested when fatigue and low libido overlap. Additional baseline items include vitamin D, urinalysis, and hormone measurements that clarify true deficiency.
Total testosterone alone is described as insufficient for a credible diagnosis in many men. Free testosterone measured with high-quality methodology is recommended, including dialysis-based techniques and LC-MS/MS support. Prolactin is included because elevations can mimic androgen deficiency symptoms and are often missed. FSH and LH are labeled mandatory for localization across the hypothalamic, pituitary, and gonadal axis. Estradiol testing is recommended using an ultrasensitive assay rather than a broad total estrogen measurement. Sex hormone binding globulin is used to interpret gaps between total and free testosterone results. Past exposure to anabolic steroids or corticosteroids like prednisone is noted as a factor influencing this axis.
Ongoing monitoring begins after therapy starts, with timing tied to half-life, dosing frequency, and peak and trough behavior. Follow-up total and free testosterone plus ultrasensitive estradiol are suggested around two months after initiation in common regimens. Sampling is advised at the nadir, meaning the low point right before the next dose would occur. Complete blood count with hemoglobin and hematocrit is presented as mandatory because polycythemia can develop on androgens. Iron studies are paired with red cell results so responses like phlebotomy are not used blindly. PSA is emphasized for ongoing prostate oversight, with caution that rising values can reflect cancer, BPH, or prostatitis. Repeated FSH, LH, prolactin, and binding globulin are described as unnecessary once exogenous testosterone suppresses gonadotropins. Secondary surveillance can include lipid trends, blood pressure, and metabolic panels when comorbid disease requires monitoring.
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Key Takeaways
- Baseline evaluation should include CBC, metabolic panel, A1c, lipids, and PSA.
- Total and free testosterone with quality assays help avoid misleading results.
- FSH, LH, prolactin, and ultrasensitive estradiol clarify diagnosis before therapy.
- Follow-up testing should target nadir timing and track hematocrit for polycythemia risk.
- PSA trends need interpretation alongside BPH or prostatitis, not only cancer fear.