Blood count
Red Blood Cells
LOINC 789-8 · /uL
What it is
The red blood cell (RBC) count is the number of red cells in your blood. These cells carry oxygen throughout the body.
Why it matters
It is a core part of diagnosing anemia and other red-cell disorders, read with hemoglobin and hematocrit.
What high values can mean
A higher count can reflect dehydration, smoking, altitude or an overproduction of red cells.
What low values can mean
A lower count points to anemia from blood loss, nutrient deficiency or reduced production.
How to improve it
Treating the cause — iron or vitamin status, hydration, or an underlying condition — restores the count.
Food & lifestyle
Iron-rich foods with vitamin C, plus adequate B12 and folate, support healthy red-cell production.
Preparing for the test
Part of a complete blood count (CBC); fasting is not required.
When to talk to a doctor
Discuss a low or high RBC count with a doctor, especially with fatigue, breathlessness or dizziness.
Related markers
Sources
- MedlinePlus (NIH)
- Testing.com (AACC)
Content reviewed on June 26, 2026
Medical disclaimer
This content is for educational purposes only. It is not medical advice and does not diagnose, treat, or prevent any condition. Reference ranges vary between laboratories — always use the range printed on your report and discuss your results with a healthcare professional.
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