HIV PCR -- screening "window"

[Yelnif]

Basically, PCR amplifies DNA.  The only requirement for this is that one
molecule of target DNA be present and the terminal 15-20 nucleotide known
(on each end of the target DNA).  PCR amplifies the DNA between the known
sequences.  Because HIV integrates its genetic material into the host
chromosome and the entire sequence of the HIV genome is known, it is
possible to identify contaminate blood samples.  So, there is no "window,"
if the HIV DNA is present it will be identified.
-Jim Finley, grad student-virology, UAB