[thedoc (OP)]

Rick asked the Naked Scientists:
   Have been getting conflicting answers on the question of a saliva swab for the purpose of "dna" after my transplant.  I sent one in for an ancestry test and didn't come back being related to the people I should have.  I know about the blood since I went from A  to B
What do you think?

[exothermic]

Depends entirely on the testing methodologies being utilized.

In terms of which would provide optimal accuracy.... it would be blood. DNA methylation & hydroxymethylation are tightly regulated in living cells and saliva is primarily dead cells