RBC
Red blood cells (RBC) carry oxygen from the lungs to the rest of the body and bring carbon dioxide back.
Red blood cells (RBC) carry oxygen from the lungs to the rest of the body and bring carbon dioxide back. They are made in the bone marrow and live for about four months. The test counts how many red blood cells there are in a given volume of blood, and it is read together with haemoglobin and haematocrit.
Fluid balance matters: being dehydrated makes the count read higher. Intake of iron, vitamin B12 and folate, heavy menstruation, blood donation, smoking, living or training at high altitude, sex, age and pregnancy also play a part.
Foods that help
Meat, fish, eggs, dairy, legumes, whole grains and dark leafy greens provide the iron, B12 and folate the bone marrow uses to make red blood cells. Drinking enough fluid before the test gives a fair reading.
Foods to limit
Large amounts of alcohol affect red blood cell production, and coffee and tea with meals reduce iron uptake.
Track it through the year
One value is a snapshot. Following it up shows whether what you changed is working.
Related markers
Educational information only — not a diagnosis. Every result is checked against safe limits, and anything critical is escalated for follow-up.
See all 84 markers →