Red cell distribution width
(RDW)

Sample type

Whole blood ( EDTA Blood)

Uses

It measures the differences in the volume and size of your red blood cells (erythrocytes), The RDW test is used to help diagnose types of anemia and other medical conditions including:

• Thalassemia, which are inherited blood disorders that can cause severe anemia

• Diabetes mellitus

• Heart disease

• Liver disease

• Cancer

Precautions

Person should be in usual diet

Interfering factors

1. dietary changes can affect the results of RDW TEST

2. Results of MCV

Pre analytical errors

1.Contamination from infusion route.

2.Hemolyzed, clotted, and insufficient samples.

1. Inappropriate containers.

Corrective action

appropriate transport and storage instructions should be allowed.

Post analytical errors

Wrong calculation of RDW results

Corrective action

The calculation that doctors use for this is (RDW-SD)/(MCV)×100.

Reference ranges

A normal range for red cell distribution width is 12.2 to 16.1 percent in adult females and 11.8 to 14.5 percent in adult males.