What Is A Red Blood Cell (RBC) Count?
A red blood cell (RBC) count is a blood test that can provide information about how many red blood cells are in a person's blood. This test might be done as one component of a complete blood cell (CBC) count. The RBC count is typically not used alone, and may be less helpful to a physician than other blood tests such as a hematocrit and a hemoglobin test.
An RBC count that is higher or lower than expected could result from several different diseases or conditions. This test is not specific enough to diagnose any particular disease, but instead is just one marker that a physician may use, especially in the case of a heme disorder. Heme is an important component of blood that is composed of iron and is gives blood its red color.
Reference Ranges For An RBC Count
An RBC count is the number of red blood cells per volume of blood, and may be reported in millions of cells in a microliter or blood or millions of cells in a liter of blood. Labs may use other units to report the number of RBCs, and will also have variations in what is considered a normal range. The table below contains an example of a normal range of RBCs. A "normal" RBC count may also vary slightly from person to person. Check with your physician if you have questions regarding your RBC count and what it could mean for your health.
|Example Red Blood Cell (RBC) Count Reference Ranges|
|Approximate Range for Women||4.2 to 5.4 million/mcL|
|Approximate Range for Men||4.7 to 6.1 million/mcL|
|Approximate Range for Children||4.6 to 4.8 million/mcL|
|Expressed in million red cells per microliter (mcL) of blood|
What Is The RBC Count Used For?
Levels of RBCs out of the normal range (either higher or lower) can be an indication of certain conditions, although this test alone can not be used to diagnose. Polycythemia or erythrocytosis are terms that may be used to describe an elevated RBC count.
A higher than typical RBC count may be associated with:
- Congenital heart disease
- Cor pulmonale
- Dehydration (such as from severe diarrhea)
- Excess RBC production (polycythemia vera)
- Obstructive lung disease
- Pulmonary fibrosis
A lower than typical RBC count may be associated with:
- Bleeding (including internal)
- Bone marrow failure
- Drug side effects (such as with chemotherapy)
- Deficiencies in iron, folate, vitamin B12, or vitamin B6
- Erythropoietin deficiency
- Kidney disease
- Multiple myeloma
See also -- Video: What Your Red Blood Cell Count Means