The only recorded HIV transmission from a blood transfusion in the last 8 years has been linked to a blood donor in Missouri.
The Missouri man in his 40's donated the contaminated blood in June of 2008, according to this report released by the CDC (Centers for Disease Control and Prevention).
Only until the man donated blood a second time was the man's HIV positive status confirmed. This was in November of 2008. The blood was destroyed and the man was banned from donating more blood. During this time investigators found that blood from his first donation had been transfused into two other patients. The first patient died during surgery and it is not known if HIV was contracted. The other patient, from Colorado, received a blood transfusion in August of 2008 and later tested positive for the HIV virus.
It has been determined that the man had donated blood during the short period of time before the HIV infection could be detected with what I am assuming was an HIV antibody test.
According to the CDC the risk of contracting HIV through a blood transfusion is 1 in 1.5 million.
Even the most advanced testing such as the HIV DNA by PCR test cannot detect the presence of HIV in the first few days after infection. Time of exposure if extremely important to receiving accurate test results. It takes time for the HIV to spread and show up on even the most advanced HIV tests.
