How often should someone with erythrocytosis (increased red blood cell mass) and a high hematocrit (elevated red blood cell concentration) donate blood?

Management of Erythrocytosis with Hematocrit of 60%

For patients with erythrocytosis and a hematocrit of 60%, therapeutic phlebotomy should be performed every 4-8 weeks during initial treatment, followed by maintenance phlebotomies 2-6 times per year, with a target hematocrit of 45-50%.

Initial Assessment and Diagnosis

• A hematocrit of 60% indicates significant erythrocytosis that requires intervention, as this level is well above the threshold where RBC mass is almost always increased 1
• The diagnostic evaluation should determine whether this is primary erythrocytosis (such as polycythemia vera) or secondary erythrocytosis (due to hypoxia, smoking, or other causes) 2, 3
• Measurement of serum erythropoietin levels is a crucial first step - low levels suggest primary causes while normal/elevated levels indicate secondary causes 3

Therapeutic Phlebotomy Protocol

Initial Treatment Phase

• For a hematocrit of 60%, initiate therapeutic phlebotomy to rapidly reduce blood viscosity and associated thrombotic risk 1
• Remove 400-500 mL of blood (one unit) per session with isovolumic fluid replacement (750-1000 mL of isotonic saline) 1
• During initial treatment, phlebotomy should be performed every 4-8 weeks until target hematocrit is reached 1
• Check hemoglobin/hematocrit before each phlebotomy session to guide treatment 1

Maintenance Phase

• Once target hematocrit is achieved, transition to maintenance phlebotomy at a frequency of 2-6 sessions per year 1
• Monitor ferritin levels every 6 months during maintenance phase 1
• Target ferritin should be 50-100 μg/L during maintenance phase 1

Target Hematocrit Goals

• The optimal target hematocrit is 45-50%, which balances reduction of hyperviscosity symptoms while avoiding iron deficiency 1
• Avoid aggressive phlebotomy that could lead to iron deficiency, as microcytosis due to iron deficiency is associated with increased risk of cerebrovascular events 1
• Iron supplementation should be provided if iron deficiency develops (MCV < 80 fL) 1

Special Considerations

• Double red-cell phlebotomy (DRP) using automated component collection systems may be more effective than conventional whole-blood phlebotomy, removing more RBC mass with fewer procedures 4
• DRP can lower hematocrit by approximately 6.9% per session compared to 3.0% with conventional phlebotomy 4
• However, DRP is associated with more mild adverse events (32.5% vs 4.2%) and should be used selectively 4

Monitoring and Follow-up

• Check hemoglobin/hematocrit before each phlebotomy session 1
• Monitor for symptoms of hyperviscosity (headache, dizziness, visual disturbances, fatigue) 2
• Assess for thrombotic complications, which are a major concern in erythrocytosis 5
• Complete recovery of hemoglobin mass after blood donation takes approximately 36 days (range 20-59 days), which should guide minimum intervals between phlebotomies 6

Cautions and Pitfalls

• Avoid excessive phlebotomy that could lead to iron deficiency, as this may paradoxically increase thrombotic risk in some forms of erythrocytosis 5
• Do not perform phlebotomy in dehydrated patients, as this can worsen blood viscosity 1
• Recent evidence suggests that thrombotic risk in some forms of erythrocytosis may be independent of hematocrit levels, indicating that factors beyond blood viscosity contribute to thrombosis 5
• Phlebotomy should be individualized based on the underlying cause of erythrocytosis - primary polycythemia vera may require more aggressive management than secondary causes 3

Alternative Approaches

• For patients who cannot tolerate phlebotomy (poor venous access, cardiovascular instability), erythrocytapheresis may be considered 1
• Erythrocytapheresis allows for selective removal of red blood cells while returning other blood components, resulting in fewer hemodynamic changes 1