What are the implications of elevated hemoglobin (Hgb) and hematocrit (Hct) levels, along with hyperferremia (elevated iron levels)?

From the Guidelines

Elevated hemoglobin (Hgb), hematocrit (Hct), and iron levels should be evaluated for polycythemia vera or hemochromatosis, and treatment should be guided by the most recent and highest quality evidence, which recommends therapeutic phlebotomy and monitoring of iron levels. The patient's condition should be assessed for symptoms of hyperviscosity, such as headache and poor concentration, and therapeutic phlebotomy should be considered if the hemoglobin is more than 20 g/dL and the hematocrit is greater than 65% with associated symptoms of hyperviscosity and no evidence of dehydration 1. Initial testing should include complete blood count, comprehensive metabolic panel, ferritin, transferrin saturation, and JAK2 mutation analysis. If polycythemia vera is diagnosed, treatment typically involves therapeutic phlebotomy (removing 500mL of blood every 2-4 weeks until Hct is below 45%), low-dose aspirin (81-100mg daily), and possibly cytoreductive therapy like hydroxyurea. For hemochromatosis, regular phlebotomy (removing 500mL of blood weekly until ferritin normalizes, then maintenance every 2-3 months) is the standard treatment, as recommended by the most recent guidelines 1. It is also important to avoid iron supplements and vitamin C with meals, which increases iron absorption, and limit alcohol consumption as it worsens iron overload. The use of MRI for non-invasive quantification of liver, spleen, pancreas, and cardiac iron can guide diagnosis and management, especially in patients without homozygosity for p.C282Y and/or the presence of additional risk factors for hepatic iron overload 1. Overall, the management of elevated Hgb, Hct, and iron levels requires a comprehensive approach that takes into account the underlying cause of the condition and the most recent and highest quality evidence.

Some key points to consider in the management of these conditions include:

• Therapeutic phlebotomy is the mainstay of treatment for polycythemia vera and hemochromatosis
• Monitoring of iron levels and adjustment of phlebotomy frequency as needed is crucial
• Avoidance of iron supplements and vitamin C with meals is important to prevent worsening of iron overload
• Limitation of alcohol consumption is also important to prevent worsening of iron overload
• Use of MRI for non-invasive quantification of liver, spleen, pancreas, and cardiac iron can guide diagnosis and management.

It is essential to consult a hematologist promptly for proper diagnosis and management of these conditions, as they can increase the risk for blood clots, cardiovascular events, and organ damage if left untreated 1.

From the Research

Elevated Hgb, Hct, and Iron Levels

• Elevated hemoglobin (Hgb) and hematocrit (Hct) levels can be indicative of polycythemia vera, a myeloproliferative neoplasm characterized by an increased red blood cell mass and increased risk of thrombosis 2, 3.
• The World Health Organization's major diagnostic criteria for polycythemia vera include an elevated Hgb or Hct level, abnormal results on bone marrow biopsy, and presence of the Janus kinase 2 genetic mutation, which is present in approximately 98% of cases 2.
• Elevated iron levels can also be associated with polycythemia vera, as the disease is characterized by an increased red blood cell mass, which can lead to an increase in iron levels 3.
• Other causes of elevated Hgb, Hct, and iron levels, such as smoking, sleep apnea, and testosterone use, should be ruled out before making a diagnosis of polycythemia vera 2, 3.

Diagnostic Criteria

• The diagnostic criteria for polycythemia vera include:
  • Elevated Hgb or Hct level
  • Abnormal results on bone marrow biopsy
  • Presence of the Janus kinase 2 genetic mutation
  • Subnormal erythropoietin level (minor criterion) 2
• Bone marrow biopsy is essential for diagnosis and baseline histomorphology, and can help distinguish polycythemia vera from other myeloproliferative neoplasms 4, 5.

Treatment Options

• Treatment options for polycythemia vera include:
  • Phlebotomy to reduce Hct level to less than 45%
  • Low-dose aspirin to reduce thrombotic events
  • Cytoreductive therapy with hydroxyurea or interferon to lower thrombosis risk and decrease symptoms 2, 3, 4
• Patient selection, treatment goals, clinical endpoints, biomarkers, and event-free and overall survival should be considered when choosing a treatment option 4.