At the time of death, the organ procurement organization serving
the hospital will review medical and social histories to determine
donor suitability on a case-by-case basis. There are a few diseases
and conditions that rule out donation. If you are HIV positive, you
will not be able to donate organs. If you have cancer in a particular
organ, you cannot donate that organ. If cancer has spread through
the body, you will not be able to donate any organs. A history of
certain kinds of cancer, particularly brain tumors, may allow for
organ donation depending on the particular circumstances and how
likely it is that a particular recipient may die if the organ is not used.

In the case of death by injury, sometimes the organs are too
damaged by either the original injury, or by the problems caused
by the injury, for them to be used in other people. Rarely, the
medical examiner may not allow organ donation, but this happens
very uncommonly.

Sometimes the donor's condition changes suddenly, such as might
happen if the donor's blood pressure. unexpectedly plummets, and
the donation cannot occur quickly enough for the organs to remain
viable. Also, there are occasional situations where the donated
organs are thought to be viable, but once they are visualized in the
operating room, they are found to be damaged or otherwise
unsuitable for transplantation due to unsuspected disease. This
news can be very disappointing for the donor's family, and for the
waiting recipients, too.

All donors are tested for a wide range of diseases and conditions
before the donation takes place. Blood tests and other
examinations are done to test the function of specific organs, and
all donors are tested for HIV, hepatitis, and other viruses that
might be dangerous to transplant into a recipient.

Lastly, the donor's family is interviewed carefully in order to obtain
the potential donor's medical history. Certain behaviors prior to
death can increase the chances that a donor may have
(unsuspected) HIV disease. The Centers for Disease Control in
Atlanta, Georgia has put together a publication that includes a set
of questions that are asked of all donors. A postiive response to
one or more of these questions doesn't necessarily rule out
donation, but it may alert the donation team to potential problems.