International guidelines are strict regarding testing of people who are donating tissue, including embryos, eggs and sperm. However, most embryos that are donated were originally intended to be used by the people creating them and testing would not have been performed within the appropriate period. In these cases, the embryos may still be donated as long as the recipients are aware of the risks.
At the time of donation, the donors provide details of medical history and are tested for communicable diseases including HIV, Hepatitis, Syphilis. If the donors do not have this testing or refuse to be tested, the donation will not be accepted.