Phlebotomy for Testosterone-Induced Erythrocytosis
Therapeutic phlebotomy should remove 450-500 mL of blood (one unit) when the hematocrit exceeds 54% in men receiving testosterone therapy, with the procedure repeated as needed to maintain hematocrit below 52%. 1
When to Perform Phlebotomy
The primary indication for blood removal in patients with elevated testosterone is erythrocytosis (elevated hematocrit), not the testosterone level itself. 1
Hematocrit Thresholds for Action
- Hematocrit >52%: This represents the threshold where erythrocytosis is clinically significant and requires intervention 1
- Hematocrit >54%: Therapeutic phlebotomy is strongly indicated at this level 1
- The risk of hemoconcentration increases blood viscosity and may aggravate coronary, cerebrovascular, or peripheral vascular disease, particularly in elderly patients 1
Volume of Blood to Remove
Standard therapeutic phlebotomy removes 450-500 mL (one unit) per session, which is the same volume used for blood donation. 1
Context for Blood Volume Removal
- Each 10 mL of venous blood represents approximately 0.1-0.3% of total blood volume 1
- Total blood volume in adults ranges from 4-8 liters depending on body size 1
- A single unit (450-500 mL) represents roughly 6-12% of total blood volume
- Small blood losses via phlebotomy are naturally replenished rapidly in hours following the draw 1
Monitoring Schedule
Monitor hematocrit or hemoglobin at the following intervals: 1
- First 3 months: Most changes in hematocrit occur during this period 1
- Every 3-6 months: During the first year of testosterone therapy 2
- Annually thereafter: Once stable 2
Risk Factors for Erythrocytosis
The incidence varies dramatically by testosterone formulation: 1
- Intramuscular injections: 43.8% develop elevated hematocrit (>52%) 1
- Transdermal gel (10 mg/day): 17.9% incidence 1
- Transdermal gel (5 mg/day): 11.3% incidence 1
- Transdermal patches (nonscrotal): 15.4% incidence 1
- Scrotal patches: 5.5% incidence 1
Higher testosterone doses directly correlate with increased erythrocytosis risk. 1
Alternative Management Options
Before or alongside phlebotomy, consider: 1
- Dose reduction: Lower the testosterone dose to achieve mid-normal range levels
- Temporary withholding: Stop testosterone until hematocrit normalizes
- Blood donation: If the patient qualifies as a donor, this serves the dual purpose of therapeutic phlebotomy
Critical Safety Note
No testosterone-associated thromboembolic events have been reported to date in the literature, which is reassuring despite theoretical concerns about increased blood viscosity. 1 However, patients with chronic obstructive pulmonary disease or pre-existing conditions that increase hematocrit face greater risk and require more aggressive monitoring. 1
What NOT to Do
Do not perform phlebotomy based solely on elevated testosterone levels. 3 Men with naturally elevated endogenous testosterone (>800 ng/dL) show no clinically significant adverse effects and only minimal hematocrit elevation that does not require intervention. 3 The indication for phlebotomy is erythrocytosis (elevated hematocrit), not the testosterone level itself.