What causes high levels of EPO?
High levels of EPO can cause high levels of red blood cells. This is called polycythaemia.
The classification of polycythaemia is subdivided into primary polycythaemia (which is caused by a genetic mutation causing inappropriate production of red blood cells) and secondary polycythaemia.
Primary polycythaemia causes low EPO levels because your kidneys sense that you have enough red blood cells, so they don’t produce as much EPO.
Secondary polycythaemia is due to chronic hypoxia which results in a compensatory increase in red blood cell production. Some causes of secondary polycythaemia include:
Congestive heart failure
Chronic obstructive pulmonary disease (COPD), including chronic bronchitis and emphysema
Interstitial lung disease
Obstructive sleep apnoea
In rare cases, certain tumours can also cause your kidneys to release inappropriately excessive EPO. Anaemia may not result from kidney disease and still cause high EPO levels. Anaemia happens when you don’t have enough red blood cells or your red blood cells don’t work as they should. It can cause high levels of EPO because your kidneys sense that you don’t have enough red blood cells, so they release extra EPO. This is a normal and appropriately high level of EPO.
What causes low levels of EPO?
Chronic kidney disease (CKD) is the most common cause of low EPO levels. Damaged kidneys can’t produce as much EPO, leading to low levels. CKD and low EPO levels can lead to anaemia. Primary polycythaemia causes low EPO levels because your kidneys sense that you have enough red blood cells, so they don’t produce as much EPO.