A red blood cell count can be used to measure an increase or decrease in the number of red blood cells.
An increase in red blood cells is known as polycythaemia and a decrease is known as anaemia.
A red blood cell (RBC) count is usually carried out as part of a full blood cell (FBC) count, and can help diagnose health conditions that affect the blood.
A low red blood cell count may be a sign that you have anaemia, internal bleeding, kidney disease or malnutrition (when a person’s diet does not contain enough nutrients to meet their body's demands).
A low count may also be a sign of an iron deficiency or a vitamin B6, B12 or folate deficiency.
Read more about the red blood cell count at Lab Tests Online UK.