View Full Version : DNA and blood transfusions

Colin Parkinson
14-06-2017, 9:27 PM
Would a blood transfusion have any effect on a subsequent DNA test taken for genealogical research purposes? Any clarification would be much appreciated.

14-06-2017, 9:45 PM
According to the Scientific American Journal - No
"Studies have shown that donor DNA in blood transfusion recipients persists for a number of days, sometimes longer, but its presence is unlikely to alter genetic tests significantly. Red blood cells, the primary component in transfusions, have no nucleus and no DNA. Transfused blood does, however, host a significant amount of DNA-containing white blood cells, or leukocytes—around a billion cells per unit (roughly one pint) of blood. Even blood components that have been filtered to remove donor white cells can have millions of leukocytes per unit."
Also from Quora - Blood cells will live for about 120 days before being filtered out by the spleen, liver, and bone marrow. So, over the course of 4 months, the amount of donor blood in the bloodstream will be in constant decline, being replaced with recipient blood. After that time, there should be no trace of the donor blood in the recipient."

Just type your question Would a blood transfusion have any effect on a subsequent DNA test? in to a search engine and you will get many results all of them saying much the same thing - a blood transfusion does not alter genetic tests.

Colin Parkinson
14-06-2017, 10:48 PM
Thank you Christina, very helpful and put our mind at rest prior to trying DNA testing.

25-04-2018, 2:37 PM
Blood transfused in the UK is leucocyte poor, 90% of transfused red cell units contain <1 x 10 to the power of 6 white cells, this might sound like a lot but the normal count is 4-11 x 10 to the power of 9 - the transfused blood usually contains about 0.02% of the normal white cell count. So any effect (unless you have had major trauma with large amounts of blood transfused) will be extremely small, your own white cells will outnumber the transfused white cells by many thousands to 1

Colin Parkinson
25-04-2018, 4:39 PM
Thank you RuthM0, grateful for the full and detailed reply. Much appreciated. I have done a couple of genealogical DNA tests, had some interesting replies but await the 'brickwalls' to be knocked down.