blood test rdw high

3 min read 08-03-2025

Meta Description: Discover what a high RDW (red blood cell distribution width) blood test means. This comprehensive guide explains the causes, symptoms, and treatment options for elevated RDW, helping you understand your test results and next steps. We'll explore various conditions associated with high RDW, from iron deficiency anemia to chronic diseases. Learn how to interpret your results and discuss them with your doctor for accurate diagnosis and management.

What is RDW and Why is it Important?

A high RDW (red blood cell distribution width) on a blood test indicates that the sizes of your red blood cells (RBCs) are more varied than usual. Red blood cells are responsible for carrying oxygen throughout your body. Normally, they're fairly uniform in size. A high RDW suggests something might be interfering with their consistent production. It's not a diagnosis itself, but rather a significant clue that warrants further investigation. Understanding your RDW result is crucial for managing your health.

What Causes a High RDW?

Several factors can contribute to an elevated RDW. These include:

1. Anemia:

Iron Deficiency Anemia: This is a common cause of a high RDW. Iron is essential for RBC production; without enough, the cells become smaller and more varied in size.
Vitamin B12 Deficiency Anemia: Similar to iron deficiency, a lack of vitamin B12 disrupts RBC production, leading to size variation.
Folate Deficiency Anemia: Folate is crucial for cell growth and division, impacting RBC size consistency.

2. Chronic Diseases:

Chronic Kidney Disease: Kidney disease often affects RBC production, leading to abnormalities in size and shape.
Cancer: Some cancers can impair the bone marrow's ability to produce healthy red blood cells.
Inflammatory Diseases: Conditions like rheumatoid arthritis and lupus can interfere with red blood cell production.
Alcohol Abuse: Excessive alcohol consumption can lead to various nutritional deficiencies and impair red blood cell production.

3. Other Factors:

Thalassemias: These inherited blood disorders affect hemoglobin production, leading to changes in RBC size and shape.
Sickle Cell Anemia: This inherited condition results in abnormally shaped red blood cells.
Myelodysplastic Syndromes (MDS): These are a group of bone marrow disorders that can cause abnormalities in blood cell production.
Medication Side Effects: Certain medications can affect blood cell production, causing an elevated RDW.

Symptoms of a High RDW

A high RDW itself doesn't always present noticeable symptoms. Instead, the underlying cause of the elevated RDW is what typically produces symptoms. These can vary depending on the specific condition but may include:

Fatigue and Weakness: A common symptom of anemia, due to reduced oxygen-carrying capacity.
Shortness of Breath: Difficulty breathing due to lack of oxygen.
Pale Skin: A visible sign of anemia.
Headaches: A consequence of reduced oxygen supply to the brain.
Dizziness and Lightheadedness: Similar to headaches, caused by lack of oxygen to the brain.
Rapid Heart Rate (Tachycardia): The heart works harder to compensate for reduced oxygen levels.

How is a High RDW Diagnosed?

A high RDW is typically discovered through a complete blood count (CBC) test. This routine blood test measures various components of your blood, including RDW. If your RDW is elevated, your doctor will likely order further tests to determine the underlying cause, such as:

Iron studies: To check for iron deficiency.
Vitamin B12 and folate levels: To assess for deficiencies.
Peripheral blood smear: A microscopic examination of your blood to assess the size and shape of your RBCs.
Bone marrow biopsy: A more invasive procedure, used in cases of suspected serious conditions like MDS.

Treating a High RDW

Treatment for a high RDW focuses on addressing the underlying cause. This may involve:

Iron supplements: For iron deficiency anemia.
Vitamin B12 or folate supplements: For respective deficiencies.
Medication adjustments: If a medication is causing the high RDW.
Treatment for chronic diseases: Managing underlying conditions like kidney disease or cancer.
Lifestyle changes: Such as dietary changes or alcohol reduction.

When to See a Doctor

If you experience any of the symptoms associated with a high RDW, or if you receive a blood test result showing an elevated RDW, it's essential to consult your doctor. Early diagnosis and treatment of the underlying cause are crucial for preventing potential complications.

Disclaimer: This information is for educational purposes only and is not intended as medical advice. Always consult your healthcare provider for diagnosis and treatment of any medical condition.