Red Blood Cell Count Test
Also known as: RBC, Erythrocyte Count, Red Cell Count
What is Red Blood Cell Count?
Red blood cells (RBCs) carry oxygen from your lungs to every cell in your body and return carbon dioxide to your lungs. The RBC count measures the number of red blood cells in a sample of blood.[MedlinePlus (NIH)]
What This Test Measures
This test counts the number of red blood cells per microliter of blood. It is part of a complete blood count (CBC) and helps assess oxygen-carrying capacity.[Mayo Clinic]
Why It's Important
RBC count helps diagnose anemia, polycythemia, and other conditions affecting red blood cell production or destruction.[MedlinePlus (NIH)]
Abnormal RBC counts can indicate dehydration, bone marrow problems, kidney disease, or nutritional deficiencies.[Cleveland Clinic]
Who Should Get This Test?
RBC count is part of routine complete blood count testing.
Risk Factors
- Routine health screening (part of CBC)
- Fatigue, weakness, or shortness of breath
- Suspected anemia
- Heavy menstrual bleeding
- Known nutritional deficiencies (iron, B12, folate)
- Chronic diseases (kidney disease, cancer, autoimmune)
- Before and after surgery
- Monitoring chemotherapy effects
- Living at high altitude
- Family history of blood disorders
Screening Schedule
Included in routine annual bloodwork as part of CBC. More frequent monitoring for chronic conditions.
What Happens During the Test
A blood sample is drawn from a vein. RBC count is performed by automated analyzers as part of a complete blood count.
Duration
5 minutes for the blood draw; results usually available same day
Discomfort Level
Minimal - brief pinch from needle insertion
Risks & Side Effects
RBC count testing through blood draw carries very few risks.
- •Minor pain or bruising at the needle site
- •Slight bleeding
- •Rarely, lightheadedness
- •Very rare risk of infection
Normal Range
For men: 4.7 to 6.1 million cells/mcL. For women: 4.2 to 5.4 million cells/mcL.
Note: Normal ranges vary by laboratory and may differ at high altitudes.
Source: MedlinePlus (NIH)Unit Conversion
Convert between million/mcL and ×10¹²/L
| million/mcL | ×10¹²/L |
|---|---|
| 3.5 | 3.5 |
| 4 | 4 |
| 4.5 | 4.5 |
| 5 | 5 |
| 5.5 | 5.5 |
| 6 | 6 |
High Values
High RBC count (polycythemia) can be caused by dehydration, smoking, living at high altitude, lung disease, kidney tumors, or polycythemia vera. It thickens blood and increases clot risk.[Mayo Clinic]
Low Values
Low RBC count indicates anemia. Causes include iron deficiency, vitamin B12 or folate deficiency, blood loss, bone marrow disorders, chronic disease, and certain medications.[Cleveland Clinic]
Test Limitations & Accuracy
RBC count alone does not identify the cause of abnormalities.
- ⚠Dehydration falsely elevates RBC count (hemoconcentration)
- ⚠Overhydration falsely lowers RBC count (hemodilution)
- ⚠Normal RBC count can exist with abnormal hemoglobin
- ⚠Does not indicate RBC function or quality
- ⚠Must be interpreted with hemoglobin, hematocrit, and indices
- ⚠Varies with altitude, age, and pregnancy
- ⚠Recent blood loss may not be immediately reflected
Alternative & Complementary Tests
RBC count is interpreted with other CBC components.
Oxygen-carrying capacity measure
Percentage of blood that is RBCs
RBC size and hemoglobin content
To assess bone marrow RBC production
For suspected iron deficiency anemia
For macrocytic anemia
Frequently Asked Questions
How can I increase my red blood cell count?
Increase RBCs by eating iron-rich foods (red meat, beans, spinach), vitamin B12, folate, and vitamin C (helps iron absorption). Stay hydrated and exercise regularly. Treat any underlying conditions.
Source: Cleveland ClinicReferences
Related Condition Guides
Medical Disclaimer
This information is for educational purposes only and is not intended as medical advice. Always consult with a qualified healthcare provider for interpretation of test results and medical decisions.
Track your Red Blood Cell Count results over time
Start Tracking Free