RDW (Red Cell Distribution Width)

What is RDW (Red Cell Distribution Width)?

Red blood cell (RBC) distribution width (RDW) is used as a measure of the range in size and volume of circulating erythrocytes. RDW helps to quickly identify if there is an increased presence of large or small RBCs which can indicate conditions such as anemia, vitamin deficiency or other underlying health issues. RDW is a part of a complete blood count and is often accompanied by a mean corpuscular volume (MCV) test.

Preparation for RDW Test

No special preparation is needed before an RDW test. Your doctor will take a sample of your blood and send it to a lab for analysis. Make sure to tell your doctor if you are taking any medications as they may affect the results of the test.

Procedure for RDW Test

The RDW test requires a sample of your blood to be taken from your arm. The sample is then sent to a lab where it is analyzed to measure the distribution of red blood cells in your blood.

Types of RDW

There are two types of RDW tests: mean cell volume (MCV) and red cell distribution width (RDW). MCV is the average size of red blood cells, while RDW is the variation in size and volume of circulating erythrocytes. MCV and RDW are usually tested together and can indicate different conditions.

Risks of RDW Test

RDW tests are a safe and straightforward procedure. The only potential risk of the test is a minor discomfort when the blood sample is taken from your arm.

Why is RDW Test Done?

RDW tests are commonly done to screen for anemia. RDW tests are also used to screen for other conditions such as vitamin deficiency, liver disease and some types of cancers.

When is RDW Test Done?

RDW tests are usually performed when a person has symptoms of anemia. Anemia can present itself in various ways including fatigue, pale skin, and heart palpitations. RDW tests may also be ordered if other blood tests indicate a possible issue. In some cases, a doctor may order an RDW test if an individual is taking a medication that could interfere with the results.

Interpreting RDW Test Results

RDW test results can help identify if a person is anemic. RDW results are given as a number (expressed as a fraction or percent), and values higher than normal may indicate anemia. The normal range for RDW is usually between 11-15%. If the RDW tests indicate anemia, the doctor may order additional tests to determine the cause of the anemia.