High RDW-SD and RDW-CV on Blood Test

rdw high blood test

You might already know that it is possible to count the variety of red cell in your body. What you may not understand is that you can go to a laboratory to countthe varying sizes of red blood cell volume. The medical professionals describe this procedure as RDW or “red blood cell distribution width”.

It is sometimes crucial to examine the red cell distribution width, which is usually between 11 and 15. The test is typically a part of a Complete Blood Count (CBC) and suggests higher variation in size when the numbers are high. Keep checking out to find out more about high RDW and what might be the reason behind your RDW high count.

What Is RDW on Blood Test?

RDW is a red cell criterion that basically counts or determines the distinction in volume or size of red cells in a sample. Various kinds of hematology analyzer instruments are often utilized to determine red cell distribution width– it is called RDW-CV when reported as coefficient of variation (CV) and is called RDW-SD when reported as standard discrepancy (SD).

RDW-SD takes measurements in “fL” and basically measures the width of red cells size distribution pie chart – it calculates the width at the 20 % height level of the histogram. The average RBC size for that reason has no result on this parameter and you get MCV or imply corpuscular volume.

On the other hand, RDW-CV is expressed in portion and is determined from MCV and conventional deviation as follows:

Information verified by the iytmed.com team.

RDW-CV (in percentage) = 1 SD of RBC volume/MCV x 100 %.

What Does High RDW-SD Mean?

You can have high RDW-SD or low RDW for various reasons. If you have seen RDW high, this may indicate different things too. Your RDW high, which is above 14.5 %, suggests that your red cells differ a lot in size. This might take place due to many different reasons, and to recognize the concern, it is essential making a contrast to the MCV or indicate corpuscular volume, which is the average amount of space each red cell occupies in your blood sample.

Increased RDW and Increased MCV
When the MCV and RDW levels are enhanced, it might be due to a liver disease. Your liver plays a big role in filtering hazardous chemical compounds and after that assisting it eliminate of your system. When it cannot remove dangerous compounds, this might leave an impact on the size of your red blood cells. You might also discover increased levels of MCV and RDW due to hemolytic anemia, a condition characterized by early damage of your red blood cells. Often, you get your RDW blood test high due to vitamin B-12 shortage in your body. Your body needs these necessary vitamins to perform certain chemical procedures and bodily functions.

High RDW and Low MCV
In many cases, you might see RDW blood test high with lower levels of MCV. Once again, you might see this scenario due to many different reasons, with among the most common being iron shortage in your body. The insufficient supply of iron in your body will cause iron shortage anemia that causes a decline in hemoglobin in your blood. Hemoglobin in your blood is essential for moving oxygen on a cellular level. When there isn’t enough iron to make hemoglobin, it will lead to anemia, which will decrease your MCV levels while keeping RDW high.

You may also notice the very same circumstance due to thalassemia intermedia, a blood disorder triggering impaired production of specific components that play a role in the production of hemoglobin. This will lead to fragmented blood cells that in turn will cause the MCV to be low and the RDW to be high. It generally implies your blood cells differ a lot in size, but those cells don’t take a great deal of area, resulting in low MCV levels.

High RDW and Normal MCV
There can be another possibility when you see your RDW high. You in some cases see your RDW levels on the greater side with your MCV levels entirely typical. This typically implies that vitamin-B12 is inadequate, though it has not fallen listed below the preferred level. It may likewise indicate the beginning stage of iron shortage anemia.

Reyus Mammadli

As a healthy lifestyle advisor I try to guide individuals in becoming more aware of living well and healthy through a series of proactive and preventive measures, disease prevention steps, recovery after illness or medical procedures.

Education: Bachelor Degree of Medical Equipment and Electronics.

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  1. Sam Wood

    It is virtually impossible to discuss the RDW element of a blood test without including MCV. Mean corpuscle value (MCV) goes hand in hand with red-blood cell-distribution width (RDW) in regards to anemia and other hematology disorders, and the worth of both are affected by each other. For example, low MCV levels in combination with normal RDW might indicate chronic disease, while low MCV combined with low RDW can signify iron shortage. In the exact same respect, a normal MCV reading in mix with normal RDW might represent a chronic disorder and normal MCV integrated with high RDW can symbolizes a B12 deficiency.

  2. Carmen Bernier-Grand

    My values:

    MCV 91.3 fl (Normal)

    RDW-CV 14.90% (slightly high)

    RDW-SD 50 fl (Slightly high)

    B12 deficiency?


    Just had a blood test. RDW SD is 47.1
    MCV is 93.

    What does this indicate?