Hematocrit Management in Testosterone Therapy

Threshold for Intervention

• The Endocrine Society Clinical Practice Guideline (2018) and the European Association of Urology guideline (2025) recommend stopping testosterone therapy and considering therapeutic phlebotomy when hematocrit exceeds 54 %. [1][2]3

Monitoring Protocol

• Perform a baseline hematocrit measurement before initiating testosterone therapy. [1][2]
• Re‑measure hematocrit 3–6 months after therapy start to detect early rises. [1][2]
• Conduct annual hematocrit checks for ongoing surveillance. [1][2]

Management of Elevated Hematocrit (>54 %)

• Discontinue testosterone until hematocrit falls to a safe level. 2
• Evaluate secondary causes of erythrocytosis, including screening for hypoxia and assessing for obstructive sleep apnea. [2][1]
• Re‑initiate testosterone only after hematocrit normalizes, using a reduced dose. [1][2]
• Therapeutic phlebotomy may be used as an adjunct, but dose reduction or discontinuation remains the primary strategy. [1][2]

Baseline Contraindications

• Do not start testosterone in patients with a baseline hematocrit >48 % at sea level. 2
• Do not start testosterone in patients with a baseline hematocrit >50 % who live at higher altitudes (greater risk of exceeding 54 % during treatment). 1

Special Considerations

• Men residing at altitudes >5,000 ft may require a higher hematocrit threshold before intervention. 1
• Routine obstructive sleep apnea screening is advised because untreated sleep apnea can independently raise hematocrit and compound testosterone‑related erythrocytosis. [1][2]