Labwise

Labwise › Tests › Complete blood count (CBC)

RDW%

RDW describes how much red blood cells vary in size. Wider variation is often seen alongside iron or vitamin changes.

See your own RDW on its range.

Labwise reads the PDF or a photo of your lab report on your iPhone and explains every test like this page does. Nothing leaves your phone.

What RDW measures

RDW describes how much red blood cells vary in size. Wider variation is often seen alongside iron or vitamin changes.

If your RDW is low

A low RDW is not usually a concern; labs often print only an upper limit.

Worth asking your clinician: Only alongside other CBC questions.

If your RDW is high

A wider spread of red cell sizes often appears when new cells differ from older ones, for example when iron or vitamin levels are changing.

Commonly associated with

Worth asking your clinician: How it fits with MCV and hemoglobin.

Typical reference range

GroupTypical range
Adults11.6 – 15.4 %

Typical adult values used by many US labs. Your own report prints the range your lab validated for its method, and that range is the one that counts. Labwise always uses the printed range first.

If it is within range

Your red cells vary little in size, which is typical.

Also listed as

Red Cell Distribution Width, RDW-CV, RDW-SD

Related tests

This page is general information about what a laboratory test measures and what results outside a reference range are commonly associated with. It is not medical advice, does not diagnose any condition and does not replace your clinician. Discuss your results with your healthcare provider.