1. What is the RDW in a blood test?
RDW stands for Red cell Distribution Width in English which means red blood cell distribution.
RDW tests for changes in red blood cell size and shape.
In healthy people, the RDW index in a blood test ranges from 9 to 15%.
If the RDW is lower or higher than 9-15%, then the body is having problems.
The higher the RDW value, the more altered the red blood cell distribution.
In RDW, there are 2 types, which are Red Cell Distribution Width - Standard Deviation (RDW-SD) and The Red Cell Distribution Width-Coefficient of Variation (RDW-CV), in which:
RDW-SD to give true volume parameter 
RDW-CV gives % value.
Reference value range of 2 parameters:
RDW-SD: 29-46 fL
RDW-CV: 11.6 – 14.6% (for adults)
2. How does the relationship between MCV and RDW affect the body?
MCV, or Mean Corpuscular Volume represents the average size of red blood cells. Based on RDW and MCV, doctors can diagnose abnormalities in the body.
In healthy people, the average size of red blood cells is usually between 80 - 96 fL.
When testing blood, if the RDW is normal but the MCV does not range in the acceptable range, it may indicate that the patient has health problems.
Normal RDW and low MCV: The patient may have chronic anemia, heterozygous halassemia, or hemoglobin E.
Normal RDW and high MCV: The patient may have chronic liver disease or have aplastic anemia. It may be because the patient is taking antiretroviral drugs, using a lot of alcohol such as alcohol, or undergoing chemotherapy.
High RDW and low MCV: Initial diagnosis may be sickle cell anemia, iron deficiency anemia.
High RDW and high MCV: The patient may have immune hemolytic anemia, myelodysplastic syndrome, folate deficiency, or severe vitamin B12 deficiency, liver disease or are on chemotherapy.
High RDW, normal MCV: The patient has sickle cell disease, chronic liver disease or myelodysplastic syndrome. Other problems can be the early stages of folate, vitamin B12 deficiency. It is also possible that the patient has dimorphic anemia.
Normal RDW and normal MCV: It is not necessarily okay because there is still a possibility that the patient has chronic anemia anemia due to kidney disease. Therefore, it is necessary to look at other blood indicators to evaluate the most accurate way.
3. Things to remember before taking blood for testing
To take blood for testing, it should be noted:
Do not take medication before doing blood tests: You need to notify your doctor to find a solution. There are a number of oral drugs that do not affect the blood results, the patient can still have blood drawn.
Fasting: Most doctors' blood tests require fasting for 8-12 hours for the most accurate results. Do not use stimulants before taking blood such as drinking alcohol, coffee, smoking…
4. The process of taking blood to test
The medical staff uses a small needle to take blood from the arm veins. The amount of blood taken should be enough for the test.
The blood sample is taken to the laboratory and after 60-90 minutes, the blood test results will be available. The index in the results will be read by your doctor, including the RDW results.
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