What are the causes of elevated Red Blood Cell (RBC) count?

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Last updated: April 29, 2025View editorial policy

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From the Guidelines

Elevated red blood cell (RBC) count, or polycythemia, should be managed based on the underlying cause, with a focus on reducing the risk of blood clots, strokes, and heart attacks, as evidenced by the comprehensive review of polycythemia vera 1. The condition can be primary, caused by bone marrow disorders like polycythemia vera, or secondary, resulting from conditions like chronic lung disease, living at high altitude, or dehydration.

  • Key considerations in the diagnosis of polycythemia include:
    • Determining whether the hemoglobin/hematocrit level is higher than the 95th percentile of the normal distribution adjusted for sex and race
    • Documenting an increase in the hemoglobin/hematocrit level above the baseline for an individual patient
    • Identifying PV-related features, such as thrombocytosis, leukocytosis, microcytosis from iron deficiency, splenomegaly, aquagenic pruritus, unusual thrombosis, or erythromelalgia, as outlined in the classification of polycythemia 1 Management depends on the underlying cause and may include:
  • Phlebotomy (blood removal) for severe cases
  • Hydration to reduce blood thickness
  • Treating the underlying condition
  • Medications like hydroxyurea (starting at 500-1000 mg daily) or interferon alpha to reduce RBC production in cases of polycythemia vera
  • Aspirin (81-100 mg daily) to reduce clotting risk, as supported by the clinical recommendations for polycythemia vera 1 Patients should avoid smoking, stay well-hydrated, and exercise moderately to reduce the risk of complications. Regular monitoring of complete blood counts is essential, and any symptoms like headaches, dizziness, or visual disturbances should prompt immediate medical attention, as these can be indicative of increased blood viscosity and risk of blood clots, strokes, and heart attacks 1.

From the Research

Elevated RBC

Elevated red blood cell (RBC) count can be a symptom of various conditions, including polycythemia vera (PV).

  • PV is a haematological malignancy characterized by erythrocytosis, often with associated leukocytosis and thrombocytosis 2.
  • The diagnosis of PV involves careful interpretation of hematocrit values, red cell count, and red cell mass when available, and bone marrow histomorphology to distinguish PV from other JAK2V617F myeloproliferative neoplasms (MPNs) 3.
  • The World Health Organization's major diagnostic criteria for PV include an elevated hemoglobin or hematocrit level, abnormal results on bone marrow biopsy, and presence of the Janus kinase 2 genetic mutation, which is present in approximately 98% of cases 4.

Treatment of Elevated RBC

Treatment for elevated RBC count in PV typically involves:

  • Phlebotomy (PHL) to reduce hematocrit levels and prevent thrombotic events 3, 4.
  • Cytoreductive therapy using interferon-alpha or hydroxyurea to control red cell counts and reduce the risk of complications 3, 2.
  • Low-dose aspirin to reduce vascular risk factors 2, 4.
  • Smoking cessation and addressing cardiometabolic disease to reduce the risk of thrombosis 4.

Note that study 5 is not relevant to the topic of elevated RBC count.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Polycythaemia vera.

Nature reviews. Disease primers, 2025

Research

Polycythemia Vera: Rapid Evidence Review.

American family physician, 2021

Research

In vitro adsortpion of acetaminophen onto activated charcoal.

Journal of pharmaceutical sciences, 1977

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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