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Low RBC (Red Blood Cell) count in the blood

Blood test
Low RBC (Red Blood Cell) count in the blood
Last update: 02/12/2020

What is a low count of RBC in the blood called?

  • Erythrocytopenia

What is the normal RBC count in the blood?

If you need to know which are the RBC reference ranges or you require more information about the role of RBC in the blood, you can visit normal RBC (Red Blood Count) count in the blood

What does a low count of RBC in the blood mean?

A low RBC count (Red Blood Cells), also called erythrocytopenia, show a low amount of RBCs (erythrocytes) in the bloodstream. Erythrocytes are measured in millions/µl (microliter).

RBCs have a protein called hemoglobin that is the responsible of transport the required oxygen to the tissues of the body. Therefore, if there is not enough RBCs there will be a hemoglobin deficiency and the anemia will appear.

Anemia is the term referring to a low amount of hemoglobin in the bloodstream. On rare occasions it is possible the existence of erythrocytopenia without anemia. That means a low RBC count, but with hemoglobin in normal range.

Anemia is a group of disorders due to multiple reasons. There are different types of anemias, for example, iron deficiency anemia, hemolytic anemia, megaloblastic anemia or anemia of chronic disease. To diagnose each one it is necessary to study other blood assays such as the hemoglobin, the hematocrit, the MCV (Mean Corpuscular Volume), the MCH (Mean Corpuscular Hemoglobin), the MCHC (Mean Corpuscular Hemoglobin Concentration) and the RDW (Red cell distribution width).

If there is an excessive bleeding, the water from the cells is poured into the bloodstream. This process reduces the RBC count. Therefore, any disease related to a loss of blood, for example hemorrhage, ulcer or colon cancer might cause erythrocytopenia.

Erythrocytopenia or a low RBC count means:

  • Mild RBC count decrease (3.5 - 4 million/µl in adult women and 4 - 4.5 million/µl in adult men):

    RBC count is a bit low and it advisable to look other assays such as the hemoglobin, the MCV or the hematocrit to give more information.

    If those assays are in the normal range it is not a matter for concern and it is probable that the RBC count returns to normal range in the next blood test.

  • Moderate RBC count decrease (3 - 3.5 million/µl in adult women and 3.5 - 4 million/µl in adult men):

    A moderate erythrocytopenia may be due to multiple causes. It is necessary to study the other assays (hemoglobin, MCV) for a better diagnosis.

    In any case, a visit to your doctor and periodically blood test is recommended.

    A moderate erythrocytopenia may be correlated with iron deficiencyanemia or sideroblastic anemia, but it is necessary to study your symptoms and the rest of the blood test to diagnose it.

  • Marked RBC count decrease (2.25 - 3 million/µl in adult women and 2.5 - 3.5 million/µl in adult men):

    A marked erythrocytopenia is a sign of a pathological condition. It is necessary to the study the blood test assay in general to give a possible diagnosis.

    Refer your doctor the possible symptoms that you are suffering and he will decide the possible diagnosis and the proper treatment.

    A marked erythrocytopenia may be due to a prolonged bleeding, a kidney failure, a chronic disease (hepatitis C or cirrhosis) or a leukemia.

  • Severe RBC count decrease (< 2.25 million/µl in adult women y < 2.5 million/µl in adult men):

    A severe erythrocytopenia is a matter of concern and it is necessary to know the reason.

    It is highly likely the existence of anemia and it is necessary further research to find the cause and avoid cardiovascular problems.

    A severe erythrocytopenia is common in many types of anemia, such as hemolytic anemia (sickle cell disease, autoimmune anemia, etc.), megaloblastic anemia (pernicious anemia) or aplastic anemia but is advisable to study all the blood test for a better diagnosis.

Which factors can decrease the RBC count in the blood?

Some particular health situation or drugs may reduce your RBC count:

Which diseases can decrease your RBC count in the blood?

The following diseases can explain a RBC count lower than normal:

What can I do to increase the RBC count in the blood?

RBC count is related to multiple disorders so it is important to know the causes to find a proper treatment.

In general, you should follow a healthy diet with an adequate intake of iron, folic acid, copper and vitamin B6 and B12. All these substances are related to a correct production of RBC.

Erythropoietin (EPO) or a blood transfusion, under medical prescription, may also help to increase the RBC count.

Where can I find more information about RBC count in the blood?

You can visit our pages about:

Which values are considered a low RBC count in the blood?

The following values are considered to be above the normal range:

IMPORTANT: These levels are expressed in mill/µl (microliter). They are an example of a healthy woman of about 45 years old with no known disease and not taking any medication. The ranges can be different depending on the laboratory or on your personal circumstances.

RBC Count
Mild RBC count decrease
3.9 mill./µl3.8 mill./µl3.7 mill./µl3.6 mill./µl3.5 mill./µl   
Moderate RBC count decrease
3.4 mill./µl3.3 mill./µl3.2 mill./µl3.1 mill./µl3 mill./µl   
Marked RBC count decrease
2.9 mill./µl2.8 mill./µl2.7 mill./µl2.6 mill./µl2.5 mill./µl2.4 mill./µl2.3 mill./µl 
Severe RBC count decrease
2.2 mill./µl2.1 mill./µl2 mill./µl1.9 mill./µl1.8 mill./µl1.7 mill./µl1.6 mill./µl1.5 mill./µl
1.4 mill./µl1.3 mill./µl1.2 mill./µl1.1 mill./µl1 mill./µl0.9 mill./µl0.8 mill./µl0.7 mill./µl
0.6 mill./µl0.5 mill./µl0.4 mill./µl0.3 mill./µl0.2 mill./µl0.1 mill./µl-0 mill./µl 
Medically reviewed by our Medical staff on 02/12/2020


  • Concise Book of Medical Laboratory Technology: Methods and Interpretations. 2nd Edition. 2015. Ramnik Sood. ISBN: 978-93-5152-333-8. Pag. 214.
  • Laboratory tests and diagnostic procedures with nursing diagnoses (8th ed), Jane Vincent Corbett, Angela Denise Banks, ISBN: 978-0-13-237332-6, Pag. 25.

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