One of the most disregarded yet potent blood parameters is the actual Red Cell Distribution Width (RDW). Though the majority of people pay attention to hemoglobin levels or white blood cell counts, physicians understand that RDW may portend some serious health problems.
What is RDW and what constitutes a dangerous RDW level? Let us take a breakdown of it in simple terms.
What is RDW in Blood Tests?
DW is an abbreviation of Red Cell Distribution Width. As the name implies, it is used as a measure of how red blood cells (RBCs) change in size (volume). Red blood cells are generally of variable diameter (typically 6 to 8 micrometers (m)) in diameter.
- High variation of size depicts that something is going wrong. The difference is referred to as anisocytosis.
- Low RDW indicates that your RBCs are close to one another in size → normal
- Large RDW indicates large fluctuation in size → possible anemia, nutrient deficiency or chronic illness.
- DW is reported as a percentage, and is always along with a Complete Blood Count (CBC) test.
How to Measure RDW
Two types of reporting RDW There are two basic methods of reporting RDW
DW-CV: (Coefficient of Variation):
- Standard deviation MCV/mean Corpuscular Volume x 100
- Normal range: 11.0 -15.0
- S D (Standard Deviation):
- In femtoliters (fL)
Normal range: 39 to 46 fL
The majority of laboratories utilize RDW CV since it shows the percentage value, which is understandable.
- Normal range of RDW
- Adults: 11- 15 percent
- Children: A bit higher range can be accepted
- Newborns: RDW is naturally elevated
Anything beyond 15% is already regarded as a high percentage and the higher the percentage then the stronger the fear.
What Level of RDW is Dangerous?
Doctors categorize high RDW levels into mild, moderate, and severe stages.
| RDW Range | Severity | Possible Causes |
| 14.5% – 18% | Mild anisocytosis | Infections, early iron deficiency, temporary stress on the body |
| 18% – 26% | Moderate anisocytosis | Severe iron deficiency anemia, megaloblastic anemia (B12/folate deficiency) |
| Above 26% | Severe anisocytosis (dangerous) | Bone marrow disorders, sideroblastic anemia, myelofibrosis, advanced chronic disease |
- A DW greater than 18 per cent must be examined with seriousness
- RDW over 26 percent is regarded as perilous and is normally related to serious blood disorders or to chronic conditions.
Why High RDW is risky
An RDW above the normal range indicates that your red blood cells are very different in size. This produces two significant effects:
Oxygen Transport Incompetence
Smaller or abnormal-shaped cells lack the capacity to transport oxygen effectively denying your tissues of oxygen. This causes fatigue, shortness of breath and weakness.
Marker of (Underlying) Disease
The onset of High RDW may be preceded by the onset of other more recognizable symptoms It may indicate nutritional deficiencies, anemia or even some chronic diseases underlying. Other studies, in fact, reveal that the higher the RDW is the higher the likelihood that an individual will experience a mortality when aged above 45 years. That is simply to say, it is not a figure on a report, but it has the potential to determine health risks in the long run.
The symptoms of High RDW
High RDW does not necessarily have symptoms. But the resulting conditions that come with it tend to leave visible symptoms including:
- Constant exhaustion and tiredness
- Lightheadedness or dizziness
- Fast heart beat (palpitation)
- Pale,Skinned (or yellowish)
- Difficulty instanding, catching the breath
- Cold hands and feet
- Frequent infections
- Headache, and poor concentration
When you see a combination of these symptoms it is advised to visit a physician and undergo a CBC test.
Reasons to High RDW
High RDW levels are triggered by a couple of health problems Let us divide them:
1. Nutritional Deficiencies
- Iron deficiency anemia: this is the most prevalent one. Without iron, your red blood cells cannot be healthy.
- Vitamin B12 deficiency: B12 deficiency causes huge abnormal shaped RBCs (megaloblastic anemia).
- Folate deficiency: Like the deficiency of B12, it improperly forms the RBCs.
2. Blood Disorders
- Sickle anemia
- (Thalassemia which is an inherited disease)
- Mixed anemia(iron deficiency + vitamin deficiency)
- Autoimmune hemolytic anemia
3. Chronic Diseases
- Heart diseases and they are disease and congestive heart failure
- Cirrhosis
- Kidney and diabetes
- Autoimmune conditions
4. Other Causes
Alcohol abuse
Colorectal cancer
Myleofibrosis (bone marrow cancer)
Cold agglutinin disease
Is Low RDW an Issue?
High RDW is abnormal but low RDW is normal and indicates uniform cell size. It also does not tend to indicate a disease. Actually, an RDW of low value is desirable.
Severe RDW and Anemia
The most typical disorder connected with high RDW is anemia. There are various types.
- Anemia, iron insufficiency -> Deformation of RBCs, increased RDW
- Vitamin B12/Folate anemia lack-> big RBC, high RDW
- Mixed anemia → small and large cells, high RDW
RDW and Mortality Risk
Studies indicate that individuals with a high RDW are at a higher risk of having severe health outcomes:
- Cardiovascular Risk: RDW above normal is associated with a higher rate of heart failure and heart attack.
- Chronic Diseases: RDW could be used to forecast the progression of diabetes, kidney, and cancer.
- General Mortality: people with high RDW above 45 years are more likely to die before their time than those with normal RDW.
- This causes RDW to be a robust yet underutilized diagnostic parameter.
Treatment of RDW
You do not need to freak out at the fact that your RDW level is high. Treatment varies with the cause. These are productive measures:
1. Dietary Changes
- Eat foods that are high in iron: spinach, lentils, red meat, poultry, fortified cereals
- B12 sources: eggs, milk products, fish, lean meat
- Include folate- rich foods: leafy greens, beans, citrus fruits
2. Supplements
- Orally (in case of ferrous tablets) or via injections (if directed to)
- Vitamin B12 Supplements (Injections, oral)
- Folic acid pills
3. Lifestyle Modifications
- Quit smoking
- Reduce alcohol use
- Be at or at a healthy weight
- Regular exercise will increase circulation
- Sleep at least 7-8 hours a day
4. Medical Treatments
- Severe anemia Treatment Routine blood transfusions
- Treatments of underlying chronic illnesses (kidney, liver, auto-immune disorders)
- Is cancerous to treat in case there is higher RDW indicating malignancy
Guidelines Before and After RDW Test
- Prior to prevalence
- No preparation is normally needed in general when only CBC is requested
- There might be need to fast when combined with other tests
- Take a prescription by a doctor and an ID
- The Test duration was approximately ish beaucoup of hours.
- A small venue of blood is taken from your vein
- The Process takes less than 5 minutes
- Frequent pain or pang may be experienced
- In the Test
- It is usual to have minor soreness at the place
- Pay day-to-day functioning at once
- The reports are normally made within 24 hours
RDW Test Price in India
The cost of doing the RDW test is 200-600 rupees included in the CBC test. Premium labs can charge more but there are a lot of clinics who will provide more discounts and home collection services.
Conclusion
It may appear that DW is a minor component of your blood report, and it is true; however, DW can provide great insight into your health. A high RDW fetish is
11%-15 % and anything higher than 18% should be considered.
A high concentration of RDW in the blood does not necessarily indicate the presence of serious problems, however, it is worth seeking medical attention. In most situations, RDW can be restored to normal with just dietary, lifestyle and supplemental changes.
FAQs about RDW Dangerous Levels
1. What is too large a RDW level?
Any value above 26% is hazardous as it shows a significant degree of anisocytosis which implies some disorder of the blood or bone marrow disorder.
2. Is high RDW of a temporary nature?
Yes, it can temporarily increase, when the person has an infection, when they experience stress, or when the person exercises intensively. Constant elevation would be a red flag
3. Is high RDW cancer?
Not always. Such cancers as colorectal cancer or bone marrow cancer are possible causes of elevated RDW, with far more likely causes being nutritional deficiencies.
4. How can I lower my RDW naturally?
Balanced diet, vitamin-rich foods, supplements, quitting alcohol, and an active lifestyle help manage RDW levels.5. Is low RDW dangerous?
No, low RDW is usually normal and does not indicate disease.
Refresh Date: August 29, 2025
