What is a red blood cell?
Erythrocytes are also known as red blood cells.
Red blood cells transport oxygen from your lungs to tissues throughout your body. A high red blood cell count can result from a condition that limits your oxygen supply or a condition that directly increases red blood cell production.
Causes
High red blood cell count may be caused by low oxygen levels, kidney disease or other problems.
Low oxygen levels
- Heart disease (such as congenital heart disease in adults)
- Heart failure
- COPD (chronic obstructive pulmonary disease) exacerbation
- Pulmonary fibrosis (scarred and damaged lungs)
- Other lung diseases
- Sleep apnea
- Nicotine dependence (smoking)
Performance-enhancing drugs
Certain drugs stimulate the production of red blood cells, including:
- Anabolic steroids
- Blood doping (transfusion)
- Injections of a protein (erythropoietin) that enhances red blood cell production
Dehydration
If the liquid component of the blood (plasma) is decreased, as in dehydration, the red blood cell count increases. This is due to the red blood cells becoming more concentrated. The actual number of red blood cells stays the same.
Rarely, in some kidney cancers and sometimes after kidney transplants, the kidneys might produce too much erythropoietin. This enhances red blood cell production.
Sometimes the cause of an excess number of erythrocytes are polycythemia vera or other myeloproliferative disorders.
When to see a doctor
A high red blood cell count is usually found when your doctor has ordered tests to help diagnose a condition you have.
Or your doctor may suggest additional tests to monitor your condition.
Source:
https://www.mayoclinic.org/symptoms/high-red-blood-cell-count/basics/definition/sym-20050858