Red Blood Cell Count
The number of oxygen-carrying red blood cells in a volume of blood.
| Typical reference range (male) | 4.2–5.8 x10E6/uL |
| Typical reference range (female) | 3.8–5.1 x10E6/uL |
Ranges vary by laboratory, method, age and sex: always use the range printed on your own report. Why labs differ.
What it measures
Red blood cells are produced in the bone marrow under the control of erythropoietin from the kidneys. They live about 120 days and carry oxygen using hemoglobin.
Why it matters
RBC count, together with hemoglobin and hematocrit, identifies anemia (too few) or erythrocytosis (too many).
What a high result can mean
High counts can result from dehydration, smoking, living at altitude, sleep apnea, chronic lung disease, testosterone or EPO use, and polycythemia vera. Thalassemia trait often gives a high count with small cells.
What a low result can mean
Low counts indicate anemia from blood loss, iron, B12 or folate deficiency, chronic disease, kidney disease, hemolysis or bone marrow problems.
What affects the result
Hydration affects concentration. Testosterone therapy commonly raises RBC, hemoglobin and hematocrit. Interpret with hemoglobin, hematocrit, red cell indices (MCV, MCH, RDW) and iron studies.
Units and conversion
Usually reported in x10E6/uL.
- From Million/uL: multiply by 1 to get x10E6/uL
- From M/uL: multiply by 1 to get x10E6/uL
- From x10^12/L: multiply by 1 to get x10E6/uL
- From 10^6/uL: multiply by 1 to get x10E6/uL
- From 10*6/uL: multiply by 1 to get x10E6/uL
- From x10E12/L: multiply by 1 to get x10E6/uL
- From T/L: multiply by 1 to get x10E6/uL
Also called on lab reports
RBC, Red Blood Cells, RBC Count, Erythrocytes, Red Cell Count, Erythrocyte Count
Related tests: Red Blood Cells
This page is educational and does not replace advice from a healthcare professional.