Red Cell Distribution Width
The Red Cell Distribution Width (RDW) test measures variation in red blood cell size to help diagnose different types of anemia.
The Red Cell Distribution Width (RDW) test is a blood test that measures the variation in size (anisocytosis) of red blood cells in the bloodstream. It is commonly included as part of a complete blood count (CBC).
A higher RDW value indicates greater variation in red blood cell size, which may be seen in conditions such as iron deficiency anemia, vitamin B12 deficiency, or folate deficiency. Normal RDW values suggest uniform cell size.
This test is useful in differentiating types of anemia and is often interpreted along with other parameters like mean corpuscular volume (MCV) to provide a clearer understanding of blood disorders.
The purpose of this test is to
- To measure variation in red blood cell size
- To help diagnose different types of anemia
- To assess red blood cell abnormalities
- To support evaluation of nutritional deficiencies
- To assist in interpretation of CBC results