If you get a blood transfusion can you test positive for two DNA's?

Question

If you get a blood transfusion can you test positive for two DNA's?

Answer 1

red blood cells don't have nuclei, and therefore no DNA.

Answer 2

No.

Answer 3

If it is pure red blood cells, the answer is no.  Red Blood Cells do not contain DNA.  

However, they do have surface proteins that can be marked and with the use of a Flow Cytometer can be read to see if your blood has foreign blood cells, that sort of test is used in cycling and is known as a 'ahomologous blood testing'.  It's used to test a cyclist who uses someone else's blood to increase their RBC count to carry more oxygen.