What Level of RDW is Dangerous?

High RDW Levels: What’s Normal, What’s Dangerous & What It Means

A red cell distribution width, or RDW, above 15% is abnormal and may require further investigations. A higher RDW suggests greater variation in the composition and structure of red blood cells, showing signs of underlying conditions.

What is Red Cell Distribution Width?

Red Blood Cell Distribution Width (RDW) is a blood test that measures variations in the size and volume of different red blood cells. Experts mostly include this in a complete blood count (CBC) and use it to assess any potential diseases or conditions. A higher RDW signifies conditions like anaemia or other blood-related disorders.

What are the Normal and Elevated Level Significances of RDW in an Adult?

In adults, the normal range of RDW is between 11.5% and 15.4%. While some other specific medical sources suggest 12.2% to 16.1% in adult females and 11.8% to 14.5% in adult males.

Whereas RDW above 15% is mainly flagged, and doctors suggest it is an indication of serious issues. Certain factors are responsible for higher RDW levels, which we will discuss in detail in the later sections.

What are the Factors Responsible for High RDW Levels?

The contributing factors that can cause high RDW levels in adults include:

• Nutritional Deficiencies:Low levels of essential nutrients, like iron, folate, and vitamin B12, can elevate the RDW level.
• Anaemia: MCV (Mean Corpuscular Volume) is always linked with RDW, which helps doctors to determine the types and conditions of anaemia.
• Haemolysis:It is a serious condition that results in the destruction of red blood cells within the body. Frequent destruction of red blood cells exacerbates the RDW level, leading to activation of underlying issues.
• Blood Transfusions: Red blood cells from the donor may have different sizes and shapes from the patient’s RBCs. Changes in the size of the red blood cells contribute to elevated levels of RDW.
• Pregnancy: During the third trimester, an increase in bone marrow activity brings potential changes in the production of red blood cells.

What are the Symptoms of High RDW?

These are the common symptoms of elevated levels of RDW in adults:

• Fatigue and Weakness : High RDW causes weakness and fatigue, especially in conditions like anaemia. Anaemic conditions result in the improper functioning of red blood cells, which contributes to retaining more energy, creating an oxygen abundance in the whole body.   
• Shortness of Breath : High RDW makes it difficult for the RBCs to deliver oxygen to the tissues. Insufficient oxygen supply results in suffocation and shortness of breath.
• Headaches : Improper functioning of the red blood cells can cause severe headaches due to inadequate oxygen supply to the brain tissues.  
• Dizziness and Fainting : Insufficient oxygen supply and other elevated vital signs contribute to frequent headaches, which eventually cause fainting and dizziness in older adult females. Anaemia reduces oxygen delivery to the brain tissues, creating a hypoxic condition.   
• Pale Skin : Anaemia and nutritional deficiencies affect the oxygen-carrying capacity of the blood. Due to the increased prevalence of iron deficiencies, red blood cells become thinner and smaller than normal cells, resulting in reduced oxygen delivery and pale complexions.

RDW, or red cell distribution width, determines the proper functioning of the red blood cells inside the physiological system. Improper oxygen supply to the brain tissues can cause pale complexions and fatigue.