Red Cell Distribution Width, % (RDW %, RDW-CV)

RDW (Red Cell Distribution Width) reflects the degree of variation in the size of your red blood cells (erythrocytes). Red blood cells transport oxygen from your lungs to all the cells in your body. Your cells need oxygen to grow, divide, and function properly.

If red blood cells differ too much in size, this may indicate a nutrient deficiency, inflammation, or other underlying health conditions.

🔍 Optimal RDW Values

• RDW-CV: 11.0–16.0% — normal range for adult women and men

↑ Elevated RDW:

A high RDW means there's significant variation in red blood cell size. Possible causes:

• Iron, vitamin B₁₂, or folate deficiency
• Macrocytic anemia (impaired red cell maturation)
• Chronic inflammation, hemolysis
• Liver, kidney, or bone marrow disease
• Recovery after blood loss

↓ Low RDW:

• A low RDW alone is not associated with hematological disorders
• It usually has no clinical significance if other markers are within range

🧾 Note: RDW-CV vs RDW-SD — what's the difference?

There are two types of RDW:

• RDW-CV (%) — the value shown in your lab results. It is calculated based on the average red blood cell volume (MCV) and the degree of size variation.
• RDW-SD (fL) — the actual width of the size distribution histogram, measured in femtoliters, and not influenced by MCV.

📎 Important: Your analysis shows RDW-CV — this is the value used in Healsens. Sometimes it’s labeled simply as “RDW” and shown in %, but it refers to the same thing.