Lozzie it does affect your health insurance, certainly the company i had it with asked explicitly if you had been tested in the last year before taking out the policy, i am not sure if the premuim goes up but you are obliged to inform them if you have been tested. I think that the rationale behind their thinking is that if you have gone for one, you must consider yourself at risk- in which case they do too. I don't know anyone who has had one, told and it gone up- but then i don't know anyone who has declared it. My friend had one done when he settled down with his no wife, and as he knew it could possibly affect his premium he didnt say owt (the test was neg and he went to one of those drop in centres that you just get a number and don't give your name).
I actually think its mental that this happens, i think that you should be rewarded for being sensible as opposed to being punished. I can understand those at hight risk having to pay more, escorts, known needle uses etc as its common sense that their health is more unstable than those who don't do this- but for those who just have one as a precaution before getting into a relationship when they know they want to participate in none protected intercourse,well surley they are just looking out for both their, and their partners sexual health.
My friend is a midwife and i ws supprised to learn that most expectent mothers are screened once during gestation, without their knowledge or consent. Its odd that they only tell them if its positive- i think that even though i know i am not really at risk it would be great for someone to tell me i am deffo clear.