RDW (Red Cell Distribution Width)
RDW measures how much your red blood cells vary in size. Healthy blood has cells of a fairly even size, so a wide spread is a sign that something is affecting how they're made.
Your reading
This app uses 11.5–14.5%. A high RDW often appears early in iron, B12 or folate deficiency, sometimes before hemoglobin drops. It also rises with age, inflammation and after blood loss or a transfusion. A low RDW isn't a concern.
What may help
- —Testing ferritin, B12 and folate to find the cause
- —Treating the underlying deficiency, after which RDW normalises over a few months as new cells replace old ones
When to talk to a doctor
If RDW is high together with an abnormal hemoglobin or MCV, or stays high without a clear reason.
Common questions
What is RDW?
RDW measures how much your red blood cells vary in size. Healthy blood has cells of a fairly even size, so a wide spread is a sign that something is affecting how they're made.
What is a normal RDW level?
Daygo uses 11.5–14.5% as the reference range. This app uses 11.5–14.5%. A high RDW often appears early in iron, B12 or folate deficiency, sometimes before hemoglobin drops. It also rises with age, inflammation and after blood loss or a transfusion. A low RDW isn't a concern.
How can I improve my RDW?
Testing ferritin, B12 and folate to find the cause. Treating the underlying deficiency, after which RDW normalises over a few months as new cells replace old ones.
When should I see a doctor about RDW?
If RDW is high together with an abnormal hemoglobin or MCV, or stays high without a clear reason.
Source: MedlinePlus (NIH): Complete Blood Count. Reference ranges are standard adult intervals — your own lab may report a different range for your age, sex, or method. This isn't medical advice; always go by the range on your actual results and talk to a clinician about anything that concerns you.