What is RDW ?
If you have been diagnosed with anemia or any other kind of blood disorder, then you may have noticed a section called RDW which had abnormal results. The RDW is a part of the complete blood count and helps in the determination of anemia, its type as well as other disorders of the blood.
RDW is an abbreviated form of ‘Red blood cell Distribution Width’ and helps in the calculation of different sizes of red blood cells that are present in a particular volume of blood sample.
Red blood cell distribution width and mean corpuscle value
When one is discussing red blood cell distribution width or RDW with respect to a blood test, one cannot forget it’s another aspect, i.e. the MCV or the mean corpuscle value. Both RDV and MCV go hand in hand, when it comes to cases of anemia and such other abnormalities as hematology disorders. The value of MCV influences the values of RDW and vice versa.
For example, a normal RDW that is combined with low levels of MCV indicate the presence of a chronic disease whereas low levels of RDW in combination with low levels of MCV can point to iron deficiencies. In the same way, normal MCV readings in combination with high levels of RDW can denote B12 deficiencies, while normal levels of MCV test results combined with low levels of RDW can signify the presence of chronic disorders.
Some studies have also indicated that high RDW levels and high levels of MCV, together point to folate deficiency in an individual, whereas normal levels of RDW in combination with high levels of MCV are symptomatic of pre-leukemia condition.
The calculation of RDW
The division of the standard deviation by the MCV or the mean corpuscle value and the multiplication of the subsequent result by one hundred results in the RDW value. Thus, the equation for the calculation of RDW value as per Beckman Coulter is, RDW = SD / MCV x 100.
The size or the volume of the red blood cells that are present in the blood cells is representative of the standard deviation.
Normal range of RDW values for blood tests
The normal range of RDW values are between eleven and fourteen percent. The RDW range value that is most favorable is at thirteen percent.
A higher than normal range RDW value is a good indicator of the presence of several disorders and abnormalities within an individual. A high RDW value can also assist physicians in the prediction of mortality, particularly in individuals who are known to be suffering from cancer and cardiovascular conditions.
It is a known fact that individuals whose blood test results indicate a higher than the normal RDW range at greater risks to developing health conditions than those individuals who have tested a lower than normal RDW range.
One must remember that blood test results such as RDW are merely indicators of underlying diseases or conditions and one should never jump to any conclusions. It is best to contact your health care provider for a complete physical assessment and diagnosis of illnesses, if one shows the symptoms of any medical conditions.