What Is RDW In Blood Test And What Does A High RDW Count Mean?

The blood with all its different markers is a good indicator of health. Knowing what indicator depicts can help deal with deficiencies.

RDW count stands for Red blood cell distribution width.  This count measures the size of the volume of the red blood cells and not the size of the blood cells itself. The blood cells are responsible for carrying oxygen from lungs to organs and carbon dioxide to the lungs for exhalation. If the cells vary greatly in size, it could mean any number of different worries. This test is done during a CBC or a complete blood count.

RDW count is always mentioned in conjunction with MCV or mean corpuscle value. The RDW and the MCV are spoken of together and mean different things when adjudged together.

What Does RDW Count Mean In A Blood Test?

A high RDW count with a low MCV could mean a chronic disease but a low RDW and a low MCV could mean anemia. A high RDW with a normal MCV could mean a B12 deficiency. A high MCV with a normal RDW could also show beginnings of leukemia. Both counts being high signify a folate deficiency. When your blood is tested, it is important that the size of the red cells not vary greatly. If your body is not producing normal sized cells or normal number of cells, it might overcompensate by producing larger cells, which is not necessarily helpful.

The normal range for RDW is 11 to 14 percent with the optimum at 13 percent. A high count can be caused by any health condition. If the cause is deficiencies, it can be remedied but if the cause is some other more chronic or serious condition, you need to immediately bring it to the attention of your healthcare provider.

Often a high RDW is caused either by a folate or a B12 deficiency. If you have either deficiency, you can take supplementation or increase food intake that contain B12 or folates. It is best if you do this under medical supervision. Occasionally RDW is also measured and observed for hematocrit or blood volume. A combination of MCV and RDW help identify if the person is suffering from potentially life-threatening blood loss.

An abnormal count of RDW suggests an acute blood loss with the possibility of hemorrhage. Tracking these two counts can help the medical professional to decide how much and when to give blood, if needed. A high RDW with a normal MCV usually indicates a recent hemorrhage.


  1. Jane

    My RDW count iS 14.6 and my MCV is 90.6. What does is mean?
    Also suggest me if any consultation is required?

  2. Shaili

    My RBC count is 4.24, Haemoglobin is 12.3, Haematocrit is 35.4, MCV is 83.49, RDW-CV is15.3, Neutophils is71 and Monocyte is 00.
    My Blood sugar Fasting is 235.0 and PP is 298.0 and Sugar in urine is +++.

    What could be my illness? I have been taking medicine for heart and blood sugar. Kindly suggest some remedies.

  3. Sally

    I am 69 years old and I am taking Relast infusions for Osteoporosis and now have a 9mm kidney stone. My RDW count is 14.8 and MCV is 90. I have not been contacted by PCP for further consultation concerning these counts. Should I be concerned?

  4. Rivera

    My hemoglobin 8.7 – low, RBC is 3.23 – low, hematocrit is 28.1% mch 31.00 g/dl – low, RDW 16.2% – high and my platelet count is 424 – high. What could the cause be and which doctor should I consult?

  5. Linda

    My blood work shows RDW 14.7. should I be concerned with this and what could cause this? In October-2016 I got bone marrow shots and in July-2016 I got plasma shots in my knee. Could this give a higher result?

  6. Sera

    My daughter is suffering from running nose for lat 3 months and when sleeping some sounds are coming like she has breathing problem also. Sometimes doctor say that is due to allergy and some doctor say it is adenoids. Recently we checked CBP and in this hemoglobin was 10.9 and RDW 15.4. Please give me some suggestion about this problem.

  7. John

    My platelets are low and my RDW is high. What does this mean?

  8. Tom

    I am 74 years old and my RDW count is 16.9 and MCV count is 97.3. I am on a statin and baby aspirin daily one tablet.

  9. Radia

    My daughter was just transfused three pints of blood because her hemoglobin level was 4.5. She still feels tired and weak though her hemoglobin level is 10.5 now but her RDW count is 22.7. What does this mean?

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