A high red blood cell count indicates there are too many red blood cells circulating in your bloodstream. Red blood cells (RBCs), also called erythrocytes, are produced in your bone marrow and transport oxygen from your lungs to tissues throughout your body. A high red blood cell count is also called erythrocytosis (uh-rith-roh-sie-TOE-sis).
The threshold for a high red blood cell count is somewhat different from one medical practice to another. A high red blood cell count is generally defined as more than 5.72 million red blood cells per microliter (mcL) of blood for men and 5.03 million per mcL for women. In children, the threshold for high red blood cell count varies with age and sex.
High red blood cell count
Specific causes of high red blood cell count may include:
- Anabolic steroids, which stimulate red blood cell production
- Carbon monoxide poisoning
- Congenital heart disease in adults
- EPO doping (injections of erythropoietin (EPO) to enhance athletic performance)
- Heart failure
- Hemoglobinopathies (conditions present at birth that impair the oxygen-carrying capacity of red blood cells)
- Kidney cancer
- Kidney transplant
- Living at a high altitude, where there's less oxygen in the air
- Other types of heart disease
- Other types of lung disease
- Polycythemia vera
- Pulmonary fibrosis
- Sleep apnea
- Smoking, which may result in low blood oxygen levels
Causes shown here are commonly associated with this symptom. Work with your doctor or other health care professional for an accurate diagnosis.