# RDW (red-cell distribution width)

Source: https://synapse-lifestyle.com/en/reference-guide/biomarkers/rdw

Unit: %

## What is RDW (red-cell distribution width)?

Red-cell distribution width (RDW) shows how varied your red blood cells are in size. If they're all roughly the same size the number is low; more variation is a broad, gentle signal about your resilience. A low, even value goes together with a calm, well-maintained production of red blood cells.

## What moves this value?

A shortage of iron or B vitamins and periods of heavy production or breakdown can widen the variation.

Iron-rich food, enough folate and B12 support even production. Discuss a persistently raised value with your doctor.

- [All biomarkers in the guide](https://synapse-lifestyle.com/en/reference-guide#biomarkers)

The colour zones are personal: they depend on age, sex, risk and history, and appear in the patient's own report.

Insights to discuss with the patient, not a diagnostic instrument.

Developed and reviewed with the Synapse [medical advisory board](https://synapse-lifestyle.com/en/advisory-board).