There is no blood test for HPV - that is not where it lives, you have to look at cells, as in the the HPV test from Digene which is being used to test for cervical cancer which has now become the national standard of care along with your pap. So you would have to have tissue from a place where it likes to go.

Confounding this further you could have it on tonsil cells but not anal or cervical cells, or any possible variation of this. So where are you going to collect it from? Even if you are positive for HPV, the test used in cervical is not specific for HPV type.... (So this test isn't valuable in oral cancer), that has to be done through a PRC test. Only a handful of HPV's are oncogenic, and even if someone has one of those there is no guarantee they will develop cancer. Any pathology department can do PRC testing, but it is expensive, and given that you may not be collecting cells from an area that currently is infected with HPV.... you are chasing your tail.