DNA in Transfused Blood

[Mortartube]

Hello, I have been pondering this.

Imagine that as a blood donor, I gave blood and that blood was given to a patient in hospital as a transfusion. Then imagine a short while later that the patient becomes well and goes out and commits a crime where some of their blood is spilt, (i.e they cut themselves).

Would my DNA possibly be at the crime scene and potentially lead to my arrest even if I wasn't there?

Or would my DNA be in such small amounts compared to the recipient that there could be no doubt that it wasn't me who committed the crime?

[dundurn]

Red blood cells don't have nucleii, so no DNA and therefore the majority of transfusions (using packed red blood cells) wouldn't make very much of a difference. Whole blood transfusions might show up but not for long. Any nucleated cells would be seen as foreign by the recipient's immune system and destroyed over a fairly short time scale. Bone marrow transplants might be a problem, however, particularly due to the fact that immature red blood cells, often released into the bloodstream when the body is low on oxygen carrying capacity, do have nucleii.

[Mortartube]

Thank you for that. I have been wondering for a while, but only just got around to posting the question.

[wildwood]

What a great question!

(and answer by dundurn)