Is it possible to tell a person’s ethnicity from a blood test? The answer is – not really – unless you have an extremely rare blood type linked to an ethnic minority.
I was listening to KFI radio talk show hosts John and Ken (http://www.johnandkenshow.com/) on the way home from work this week and they were talking about college applications and ethnicity. They were joking that if colleges are looking for certain types of ethnicity, it would be better for you to check that box, even if you are not of that ethnicity. And Ken mentioned that at some point, the colleges might start taking blood tests to prove that you are indeed the ethnicity that you have selected. And that got me thinking……can you prove someone’s ethnicity from a blood test?
Blood is extremely complex, but at the most basic level – there are four major blood types, A, B, AB and O and the blood is either RH negative or RH positive. The chart below shows the combinations of blood types by RH factor and the percentages by ethnicity (reference 1). Even though blood type + RH factor combinations vary by ethnicity, it is not an indicator of the person’s ethnicity.
Besides these major blood types, there are about 600 minor blood types that can be linked to a specific ethnic minority groups. For example, the blood types U-negative and Duffy-negative are linked to African and African Caribbean groups. Sickle cell disease can be detected by a blood test and this occurs 98% of the time in African Americans (reference 2).
Let’s take it one step further – can DNA testing determine ethnicity? The answer is – not really, but kind of. DNA testing is typically done with a cheek swab and the genetic markers are best used to determine if two people are related or if two people have descended from the same ancestor (reference 3). The DNA testing can give clues about the person’s ethnic origin, but it would simply give estimated percentages of how the person links to large ethnic groups like European, Indigenous America, East Asian or African.
When researching your ancenstry via DNA, even a service like that found at www.ancestrybydna.com has a disclaimer on their site: “…does not predict or establish a person’s race; it only gives an estimate of genetic ancestry or heritage…”
If we ever need to confirm that someone is the ethnic background that he checked on an application, we will need to find some other way than a blood test or a DNA test. But regardless of what kind of application it happens to be, the best application is the one that doesn’t care about the applicant’s ethnicity. That is my opinion and a survey of one.