What does RDW means? It means Random Distribution of red blood cell width. This amount informs us about the consistent size of the RBC (red blood cells). RDW is differentials of RBC. If one has symptoms of anemia, the doctor must advise him for a blood test that show your normal or abnormal RDW count. Iron deficient cells are smaller than Reticulocytes, Folic acid, and B 12 deficient cells. RDW high indicates that there is only a deficiency of B 12 or Folic acid or only iron deficiency. The normal range of RDW is about 11 to 15 %.

The RDW study shows the complete blood picture. It is an estimate of change in the size of your Red blood cells. If a person, having RDW high means that the RBC differ in size. There are many reasons of high RDW in comparison to MCV (mean corpuscular volume). If both these levels are high, there are many possible causes.

1. Liver disease.

2. Hemolytic anemia.

3. Thalessemia .

The RDW usually increased in following conditions:-

1. Folic acid deficiency.
2. Pernicious and B12 Anemia.
3. Iron deficiency combination with anemia.
4. Transfusions.
5. Alcohol abuses.
6. Heredity anemias.
7. Hemolytic anemia.
8. Sideroblastic Anemia.
9. Sickle cell anemia.
10. Membrane defects.

Low RDW means that red blood cells differ extremely little in size.

The RDW is normally decreased in following conditions:-

1. Anemia.
2. Blood loss.
3. Parasites.
4. Vitamin B6 anemia.
5. Rheumatoid arthritis.
6. Lead poisoning.
7. Chronic disease.
8. Aplastic anemia.
9. Malignant disease includes leukemia.

If the level of RDW is high and the level of MCV is normal, then it is a beginning stage of a folic acid or Vitamin B12 deficiency in the human body. Low level of RBC is the most common reason of anemia in children.