A RDW (Red Cell Distribution Width) blood test measures the variation in size and volume of your red blood cells (erythrocytes). It's a common test included as part of a complete blood count (CBC) to help doctors understand your overall blood health.
The test works by analyzing a sample of your blood using a special graph called a histogram. If your red blood cells are all about the same size, they'll be close together on the graph. However, if there's a significant variation in size, the red blood cells will be spread out across the graph, indicating a higher RDW.
A high RDW can be a sign of various conditions, including:
- Iron deficiency anemia: This occurs when your body doesn't have enough iron to produce enough healthy red blood cells.
- Vitamin B12 or folate deficiency: These vitamins are essential for red blood cell production.
- Chronic liver disease: Damage to the liver can affect red blood cell production.
- Other conditions: A high RDW can also be associated with certain types of leukemia, myelodysplastic syndromes, and other blood disorders.
A low RDW is less common, but it may suggest:
- Thalassemia: A genetic disorder that affects red blood cell production.
- Spherocytosis: A condition where red blood cells are abnormally round.
Overall, an RDW test is a valuable tool for doctors to assess red blood cell health and help diagnose various conditions.
