Red Blood Cell RBC Count
Also Known As: RBC Count, RBC Blood Test, Erythrocyte Count
What Is A RBC Blood Test?
A red blood cell count test is important to measure the amount or number of red blood cells, i.e., RBCs in your blood. Red blood cells are made in the bone marrow and contain hemoglobin, a protein that helps transfer oxygen to all body parts. In general, the amount of oxygen transported to all your body parts is based on your red blood cell count.
The red blood cell count test is often performed as a component of complete blood count or CBC test used to measure other types of blood cells in the body. Women usually have a lower RBC count as compared to men, but this level tends to decrease with age. A normal red blood count is:
In men:
- 4.7- 6.1 million cells per microliter
In women:
- 4.2- 5.4 million cells per microliter
Doctors use the results of your RBC count to diagnose certain blood-related conditions like iron deficiency anemia, a condition where red blood cells are lower than usual. It is also used to signify conditions like kidney diseases, internal bleeding, and even malnutrition (when your diet does not have enough nutrients to meet the body's needs).
What Is The RBC Blood Test Used For?
The main purpose and objective of a red blood cell count test is to determine the exact amount of RBCs in your blood and to know whether they are normal or abnormal. RBC count test is also included in your routine blood testing during checkups, mainly as a component of complete blood count. Accurate measurement of RBCs in the blood helps diagnose anemia and its different types. A low RBC count indicates anemia, but additional tests are also needed to determine the underlying cause.
Apart from anemia, the test can also indicate other underlying medical conditions like kidney cancer, white blood cell cancer, and bone marrow problems.
Why And When Do You Need A Red Blood Cell Count Test?
You are likely to undergo this test if your RBC count is too high or low. You can experience the following symptoms and conditions with a low RBC count:
- Shortness of breath
- Fatigue
- Dizziness
- Weakness or lightheadedness
- Headaches
- Increased heart rate
- Pale skin
High RBC count gives you symptoms like:
- Shortness of breath
- Fatigue
- Extreme joint pain
- Itchy skin, especially after a bath
- Tenderness in palms and soles
- Sleep disturbance
This test is almost often performed as a part of your CBC test. This procedure helps the doctor measure different blood components, including red blood cells, white blood cells, hemoglobin, hematocrit, and platelets. The RBC blood test will only be performed in a circumstance if the doctor suspects you have symptoms of low oxygen and a condition affecting the red blood cells like:
- Irregular breathing
- Bluish coloration of the skin
- Irritability and restlessness
- Confusion
What Kind Of Sample Is Required For The Test?
An RBC blood test can be performed in your doctor's office, a lab, or any other medical setting. The doctor will draw blood from your vein using a small needle. After collecting enough blood in the attached vial or tube, the sample will be sent to the laboratory for further testing.
Do You Need To Prepare For The Test?
No preparation is needed before the test; however, certain medications can affect your blood results, so make sure your doctor knows everything about them beforehand. Your doctor or healthcare provider can sometimes ask you to avoid intense exercise, stay relaxed and stress-free, drink ample water, and delay the consumption of some medicines.
Are There Any Risks To This Test?
As with any other blood test procedure, you are susceptible to bleeding, bruising, or infection at the puncture site. You can even feel mild or sharp pain with a pricking sensation when the needle enters the arm vein.
What Do The Test Results Mean?
The normal RBC range includes the following; however, these ranges can differ depending on your doctor or the chosen laboratory for testing.
- For men: 4.7-6.1 mcL
- For women: 4.2-5.2 mcL
- For children: 4.0-5.5 mcL
People with high RBC count usually have erythrocytosis, which may be due to:
- Congenital heart diseases
- Cigarette smoking
- Renal cell carcinoma, i.e., a type of kidney disorder
- Extreme dehydration
- Polycythemia vera, i.e., a bone marrow disorder that leads to excessive production of RBCs and if often linked with a genetic mutation
- Pulmonary fibrosis
Shifting to a place with a higher altitude can also alter your RBC count. It will be more for several weeks due to low oxygen in the air. Another factor affecting your RBC count includes certain medicines like methyldopa and gentamicin. Moreover, it can be due to sleep apnea, pulmonary fibrosis, and other health conditions involving low blood oxygen levels.
Lower than normal RBC count can be caused by:
- Bone marrow failure
- Anemia
- Hemolysis, i.e., RBC destruction due to blood vessel injury and transfusion
- Erythropoietin deficiency due to anemia in people with chronic kidney disorders
- Leukemia
- Internal or external bleeding
- Malnutrition
- Multiple myeloma, i.e., cancer of plasma cells in bone marrow
- Pregnancy
- Thyroid related disorders
- Nutritional deficiency like those of iron, copper, vitamin B6 or B12, and folate
Some drugs can also lower your red blood cell count like:
- Hydantoins (for seizures and muscle spasm)
- Chemotherapy drugs
- Quinidine (for irregular heartbeats)
- Chloramphenicol (for bacterial infections)
Related Test: CBC (Complete Blood Count), Iron Test, Blood Smear, Hematocrit Test.
Our clinical experts continually monitor the health and medical content posted on CURA4U, and we update our blogs and articles when new information becomes available. Last reviewed by a clinical team on January 9th, 2024.
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