CBC / Hematology
Also known as: RDW-SD, Erythrocyte Distribution Width
No common urgent flag from this test alone. However, symptoms like severe shortness of breath, extreme fatigue, dizziness, or a very fast or irregular heartbeat should always prompt immediate medical attention.
This test checks how much your red blood cells differ in size. Usually, your red blood cells are all pretty much the same size.
Your doctor orders this test to check your red blood cells. It is part of a bigger blood test. This test helps your doctor find out why you might have anemia. Anemia means you have too few red blood cells. It also helps them find other blood problems.
Reference ranges for RDW can vary depending on the lab that performs the test.
Clinical Reference
639900500985025Included in CBC panel
Educational purposes only — This information is not a substitute for professional medical advice, diagnosis, or treatment. Always discuss your lab results with your healthcare provider.