hm well im a boy so dont know the whole shebang but the routine is likely to include:
- Get there, your appointment is probably under your first name and date of birth so just go to reception and ask. As you've never been before they'll ask you to fill in a form with address/other contact details and how you want to be contacted. Also your GP. This is completely confidential - they will not pass on details to anyone without your written consent. You state how you want to be contacted, but if you need to be treated for something they are under a legal obligation to use all of your contact details to reach you I beleive.
- Go into the room after you're called. The doctor will ask you about symptoms (if you have any) and sexual history. Things like: How many people have you slept with in the last year? How long have you been with your current partner? Do you use protection for vaginal/oral sex? Have you ever had sex with someone you knew to have injected drugs? Etc. Etc. They've heard it all before and a bag of potato chips - don't be embarrassed and tell the truth - it's important for them to be able to assess what risk you might be at.
- Examination (probably internal for girls, though i can't imagine it's that invasive). If it's a male doctor there will be a female member of staff present as a chaperone. For things like warts/herpes/lice/discharge.
- Swab from vagina. For things like chlamydia/thrush I think.
- Swab from mouth. Chlamydia again I guess - don't quote me on that though.
- Urine sample - they'll give you a conatiner and you go to the toilet and do it - some places you bring it back to them and some places you put it in a little hatch. This shows up most bacterial stuff.
Depending on whether you want to (it's strongly advised), they will take a blood sample too, to test for syphillis/HIV.
You tend to get a doctor for the examination and "downstairs" swabs, and a nurse for the blood being taken and the oral swab. At some point the doctor will go out and look at your vaginal swab through I microscope - I'm guessing here because they do that for urethra swabs for boys - might not happen.
Usual time for results is around a week - they will ocntact you in the method of your preference (you fill out a form with address etc.) At the one I go to you're supposed to ring in 10 days if you haven't heard anything.
If you do turn up positive in any of the tests you'll need to go back to discuss treatment - for many things it's as simple as a cream or tablets for a week. If it's something serious they have health advisors and counsellors for you to talk to there.
Don't be worried about it - you're doing a really mature and responsilbe thing by going - they will by no means judge you and they are always extremely friendly and put you at your complete ease.
Good Luck!