There's no pass or fail results. You can still get married if you are tested positive, but its just to inform the soon-to-be married couple of the situation so that pre-caution measures can be taken to avoid the disease spreading and blooming.
Any government clinics in Selangor now have a special dedicated HIV Blood Test counter, which is only open certain hours in a day. Mr. tried to call a lot of clinics around our office area here in Seri Kembangan but it seems that they don't take appointments and you will have to queue in line for your turn. He finally managed an appointment with Klinik Kesihatan Kelana Jaya and after registration, we waited about 5 minutes for our turn and then another 10 minutes for our results - Alhamdulillah, both results were negative :)
The test kit is like a pregnancy test kit. A prick on your finger for a drop of blood - and then the blood is placed on a kit (as seen below). Wait for a few minutes, a line will be seen to indicate the result.
You should have seen Mr's face when he received the results paper. "Abang, saya dah boleh kawin lah ni kan?" he asked the nurse. "Boleh dah.. bila nak kahwin ni?"
"Sekarang jugak ni abang saya nak kawin! Dah dapat result ni, sekarang gak saya kawin!" LOL. Malu saya, org lain pandang tsk tsk.
So anyways. The key is: find a government clinic that takes appointments! Don't waste time waiting for your turn. It can take an hour or so. Of course, I recommend you the Kelana Jaya clinic.
For other lists of clinic, you may visit the JAIS website here.