What does it mean when your red cell distribution width is high?

A high red cell distribution width (RDW) indicates increased variability in the size of red blood cells. This can suggest several conditions, such as anemia, where different sizes of red blood cells might indicate a mix of types or stages of red blood cell production. Elevated RDW can also be associated with nutritional deficiencies (like iron, vitamin B12, or folate), chronic inflammation, or other underlying health issues. It’s important to interpret RDW results in conjunction with other blood tests and clinical findings for a comprehensive assessment.