About this study
The Duffy null blood type is common in people of African descent. This blood type is like the other blood types you might know about, such as A, B, AB, and O, plus Rh types (positive or negative). The Duffy blood type is separate from these. Someone can have any of these blood types and also be Duffy null. For example, a person could be O positive (O+) and Duffy null.
People with the Duffy null blood type do not have Duffy proteins on their red blood cells. They also may have a lower number of disease-fighting cells called neutrophils (a type of white blood cell) compared to people who do not have the Duffy null blood type. Despite this, they do not seem to have more illnesses than people without the Duffy null blood type. A “low” neutrophil level may actually be normal for a person with the Duffy null blood type. It is important that doctors know what is the normal level of neutrophils for people with the Duffy null blood type.
In this study, we will take a small amount of blood left over from patients' other blood tests. We will run a test on the blood samples to see if they have the Duffy null blood type. We will put together the neutrophil counts from many people to create a range of levels called a neutrophil reference range. It will tell us the lowest and highest numbers of neutrophils we would normally expect to find in a person with the Duffy null blood type.
Eligibility overview
- Hematology clinic patients up to 18 years old
- No medical condition, illness or medicine that could affect the white blood cell or neutrophil counts