From the Guidelines
Phlebotomy is typically considered when hemoglobin (Hb) exceeds 20 g/dL and hematocrit (Hct) is above 65%, associated with symptoms of hyperviscosity, as recommended by the ACC/AHA 2008 guidelines 1. The decision to perform phlebotomy should be based on both laboratory values and clinical symptoms, such as headache, increasing fatigue, or other symptoms of hyperviscosity in the absence of dehydration or anemia.
- Key considerations for phlebotomy include:
- Hemoglobin levels above 20 g/dL
- Hematocrit levels above 65%
- Presence of symptoms such as headache, fatigue, or other signs of hyperviscosity
- Absence of dehydration or anemia
- It is essential to note that repetitive phlebotomies can lead to iron depletion, decreased oxygen-carrying capacity, and increased risk of stroke, as highlighted in the ACC/AHA 2008 guidelines 1.
- The procedure should be performed cautiously, especially in elderly patients or those with cardiovascular disease, with careful monitoring for hypotension or hypovolemia during and after the procedure, as emphasized in various studies 1.
From the Research
Phlebotomy Considerations
- Phlebotomy is considered a crucial treatment for patients with polycythemia vera (PV) to reduce the risk of thrombosis 2, 3.
- The goal of phlebotomy is to maintain a hematocrit level of less than 45% 2, 4.
- Patients who require frequent phlebotomies (3 or more per year) may have a higher risk of thrombosis and may benefit from cytoreductive therapy 4.
- Phlebotomy intensity and frequency can impact the risk of thrombotic events, with increasing intensity associated with a lower risk of thrombosis 3.
Hematocrit and Hemoglobin Values
- Erythrocytosis, characterized by a hemoglobin level greater than 16.5 mg/dL in men or 16.0 mg/dL in women, is a required diagnostic criterion for PV 2.
- Hematocrit control below 45% is associated with a lower rate of thrombosis in PV patients 4.
- The exact values of hematocrit (H) and hemoglobin (Hb) that necessitate phlebotomy are not explicitly stated, but maintaining a hematocrit level below 45% is a general guideline 2, 4.