Red Blood Cell (RBC) Blood Test

What is RBC Blood Test

Red Blood Cell blood test, also termed RBC blood test is a part of Complete Blood Count (CBC) test. It is done as a part of normal routine laboratory test. Your doctor can give you this test if you show symptoms like shortness of breath, fatigue, restlessness, irritability, headache etc. Usually, anemia is detected through this RBC blood count test.

RBC Blood Test Purpose

Red Blood Cell (RBC) blood test is done as a routine blood test for various purposes. Normally RBC blood test is done with few similar tests like MCV Blood test, Reticulocyte count Blood test, MCHC blood test, MCH blood test, Hematocrit test, etc. The main purpose of RBC blood test is to

  1. Evaluate overall health condition
  2. Determine a wide range of different medical conditions
  3. Differentiate between various medical conditions
  4. Monitor the side effects of medications that are usually involved to alter RBC count
  5. Know the severity of any disease
  6. Evaluating the outcomes of any ongoing treatments like anemia treatment
  7. Determine the physical status of the patient before any surgical procedure

RBC Blood Test Importance

As RBC contains hemoglobin that is involved to carry the oxygen in our blood and reach the oxygen in all the different parts of our body, its abnormal range is harmful for our body. Yes, both the high range and low range in abnormal manner will hamper our body in a permanent way.

The lower range of RBC cause deficiency that is low oxygen status in our body. So body can not get enough oxygen as per need. If the RBC count is low in the body then either the bone marrow is not producing enough red blood cells (RBCs) or there maybe the increase rate of premature destruction of RBC. In either of these two cases, RBC count is lower than normal. As a result it impacts our other blood parameters, as well as the normal physical condition of our body.

If the RBC count is higher than normal, it causes higher viscosity of blood, so the heart can not pump the blood effectively. Also, the high chances of blockage of blood vessels can occur. Higher RBC count means either bone marrow is producing too many RBCs or there is inadequate destruction of RBCs.

Thus the importance of the RBC count is to determine

  • If any modification of the ongoing treatment is needed or not
  • Which treatment module should be appropriate for the patient

RBC Blood Test Procedure

Blood is drawn from one of your vein (usually from vein of arm) through inserting a needle for RBC blood test. No special precautions is needed for this test like no need for dietary restrictions, fluid restrictions, etc. You can go for this test any time in a day as per your convenience.

Red Blood Cell Normal Range

Normal range of Red Blood Cell (RBC) in blood is for Adult Male is 4.5 million/mm3 to 6.5 million/mm3. That means the normal average of
Red Blood Cell (RBC) in blood for adult male is 5.5 million/mm3. For menstruating females this Red Blood Cell (RBC) Count ranges from 3.8 million/mm3 to 5.8 million/mm3. This means for menstruating females the normal average of Red Blood Cell (RBC) Count is 4.8 million/mm3.

Red Blood Cell (RBC) Blood Test Low Level

If the RBC blood test count is lower than normal the reasons are the following

  • Anemia
  • Bleeding either internal or external
  • Malnutrition (Vitamin B12, Folate, Iron, Copper, Vitamin B6, Vitamin A deficiency)
  • RBC destruction due to any reason such as transfusion, blood vessel injury, etc.
  • Bone marrow failure
  • Chronic kidney disease (as there is erythropoietin deficiency)
  • Bone marrow disorder (example, Multiple Myeloma)
  • Thyroid disorder
  • Pregnancy
  • Drugs (chemotherapy drugs, chloramphenicol, etc.)

Red Blood Cell (RBC) Blood Test High Level

The red blood cell count can be higher than normal. The reasons of high RBC blood test count are the following

  • For both male and in female if the Red Blood Cell (RBC) blood test count value ranges from 7 to 8 million/mm3, then it is called polycythemia. It is a bone marrow disease where the over production of RBC occurs.
  • Higher Altitude
  • Dehydration
  • Cigarette Smoking
  • Lung Fibrosis
  • Kidney Cancer
  • Congenital Heart Disease
  • Sleep Apnea
  • Drugs (Example Methyl Dopa, Gentamicin, etc.)

Red Blood Cell (RBC) Blood Test Count and Blood Cancer

Different type of blood cancers impact the RBC productions in bone marrow. As a result, RBC blood test counts can show abnormal range.

Like in Leukemia, the bone marrow becomes ineffective to produce red blood cells (RBC) as well as Platelets. Also, in Myeloma, the bone marrow is loaded with myeloma cells so bone marrow is unable to produce RBC as well as platelets. As a result the RBC blood test value decreases.


RBC blood test count is a part of routine blood test. The level of RBC gives an idea about ovearall health condition. There are various reasons for abnormal RBC blood test count as mentioned above. Solely based on RBC blood test count, no confirmatory diagnosis can be given for any medical condition. It only gives an idea about your RBC level in your body.

Usually men have higher RBC blood test count than women. When RBC blood test count is lower than normal in men, it is alarming. One should not ignore this. Also, RBC plays various vital roles in our body including oxygen transfer, so one should not delay to get the appropriate treatment. Otherwise, fatal outcome can occur. Stay healthy and happy.


  1. William’s Hematology Book, 9th Edition
  2. Harrison’s Principles of Internal Medicine 20th edition

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