A measure of variation in red cell size, useful in anaemia work-up.
Red cell distribution width, or RDW, measures how much your red blood cells vary in size. A higher RDW means a wider mix of small and large cells, while a lower RDW means cells are more uniform.
It is a calculated index from the complete blood count.
RDW adds depth to the other red cell indices. A high RDW can be an early sign of iron, vitamin B12, or folate deficiency, sometimes before the average cell size changes. It also helps tell iron deficiency apart from a thalassaemia trait, since iron deficiency usually raises RDW while thalassaemia trait often does not.
Aniva reads your result against research-backed ranges, not just the lab's wide normal. The reference shown below is specific to this biomarker.
Typical adult range, automated count (RDW-CV):
| Measure | Typical range |
|---|---|
| RDW-CV | 11.5 to 14.5 % |
Ranges are guidance only and vary by laboratory and analyser. Read against your lab's own reference range, aligned to German practice (DGKL).
Your result shows how even your red cells are in size. Read with MCV and haemoglobin, it helps catch an early or mixed anaemia and points toward the most likely cause.
A recent blood transfusion, recent bleeding, or a mix of two anaemia types can raise RDW. Some analysers report RDW-CV and others RDW-SD, which use different scales. Delays before analysis can affect the result.
Best read with MCV and haemoglobin, and with iron studies, vitamin B12, and folate when an anaemia is suspected.
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