At what hematocrit level is phlebotomy indicated for secondary polycythemia?

From the Guidelines

Phlebotomy Indication for Secondary Polycythemia

Phlebotomy is indicated for secondary polycythemia when the hematocrit level exceeds the normal range, with the goal of reducing it to a target level.

• The target hematocrit level for phlebotomy in secondary polycythemia is generally considered to be less than 45% 1, although this may need to be individualized based on the patient's symptoms and risk factors.
• For example, a lower hematocrit cutoff of 42% may be appropriate for female patients or those with progressive or residual vascular symptoms 1.
• Phlebotomy should be performed under careful conditions with appropriate and monitored fluid replacement to avoid both hypotension and fluid overload 1.
• The goal of phlebotomy is to reduce the risk of thrombotic complications, which are more common at higher hematocrit levels 1.
• In addition to phlebotomy, other treatments such as aspirin and cytoreductive therapy may be considered in certain cases, such as in patients with low-risk polycythemia vera 1.

From the Research

Indications for Phlebotomy in Secondary Polycythemia

• Phlebotomy is indicated for secondary polycythemia when the hematocrit level exceeds 54% 2
• This threshold is based on current Canadian guidelines, which recommend regular laboratory monitoring and discontinuing testosterone replacement therapy (TRT) or reducing the dose if the hematocrit exceeds 54% 2
• A study of men with testosterone-deficient men treated with intramuscular testosterone cypionate found that 10% of men had a hematocrit ≥54%, and 33.3% had a hematocrit ≥50% during therapy 3
• Another study found that hemoglobin concentrations of 180 g/L or more (calculated hematocrit, ≥54%) were measured at 25% of appointments in men on TRT who presented for blood donation 2

Hematocrit Levels and Phlebotomy

• A hematocrit level of ≥54% is considered an indication for phlebotomy in patients with secondary polycythemia 2
• However, some studies suggest that phlebotomy may not be sufficient to maintain a hematocrit below 54% in all patients, particularly those with persistent elevations in hemoglobin levels 2, 4
• The optimal hematocrit target for phlebotomy in secondary polycythemia is not well established, but a level <45% is often recommended to prevent adverse outcomes 4, 5