RDW

Aliases: Red Cell Distribution Width, Erythrocyte Distribution Width, RDW-SD (standard deviation) test

Group: Complete blood count

Description:

The red blood cell distribution width (RDW) test measures differences in the volume and size of red blood cells (erythrocytes). Red blood cells carry oxygen from the lungs to all cells in the body. Cells need oxygen to grow, form new cells, and stay healthy. Normally, red blood cells are all the same size. A high RDW means that there is a large difference between the size of the smallest and largest red blood cells. This can be a sign of a medical condition.