What Causes High Hematocrit Levels?

Hematocrit Levels in Blood

Hematocrit is a measure of the percentage of red blood cells in your total blood volume. High hematocrit levels, known as polycythemia, can be caused by various factors. Polycythemia can be broadly categorized into two types: primary and secondary.

  • Primary Polycythemia (Polycythemia Vera):
    • Genetic Mutation: Primary polycythemia, particularly polycythemia vera, is often associated with a genetic mutation (JAK2 mutation) that leads to the overproduction of red blood cells.
    • Bone Marrow Disorder: It results from a problem in the bone marrow, where there is an overproduction of red blood cells, white blood cells, and platelets.
  • Secondary Polycythemia:
    • Chronic Hypoxia: Conditions that cause chronic low oxygen levels in the body can stimulate the production of red blood cells. Examples include chronic lung diseases (such as chronic obstructive pulmonary disease or severe sleep apnea), high-altitude living, and certain heart diseases.
    • Smoking: Smoking can contribute to secondary polycythemia by reducing oxygen levels in the blood.
    • Dehydration: A decrease in plasma volume due to dehydration can result in a relative increase in the percentage of red blood cells, leading to high hematocrit levels.
    • Kidney Disorders: Conditions such as renal cell carcinoma or certain kidney diseases can lead to increased production of erythropoietin (a hormone that stimulates red blood cell production), causing secondary polycythemia.
    • Testosterone Replacement Therapy: In some cases, testosterone replacement therapy can stimulate the production of red blood cells, leading to higher hematocrit levels.

It’s important to note that a high hematocrit level doesn’t necessarily indicate polycythemia, as it can be influenced by factors such as dehydration. Diagnosis and interpretation of hematocrit levels should be done by healthcare professionals, who may perform additional tests and consider the overall clinical picture.

If you suspect high hematocrit levels or if it is identified through a blood test, it’s crucial to consult with a healthcare provider to determine the underlying cause and appropriate management or treatment. Treatment may involve addressing the underlying condition, therapeutic phlebotomy (removing blood to reduce red blood cell concentration), or other targeted interventions based on the specific cause.