well i learned something today
i would have guessed the 1 in 500 was true when your partner had HIV but when they already have AIDS i was sure it was much higher
Once a person is known to be infected, a different blood test is done periodically to see how well the person's immune system is working. The test measures the level of CD4 lymphocytes, the type of white blood cell targeted by HIV. If the number of these cells falls below a certain level—or if the person has certain severe infections like those described earlier—then the person is said to have AIDS.
Maybe this will help