it depends on what you mean by latency period. people who contract hiv sometimes do not present symptoms for years, but they would test postitive. if you have been exposed to HIV, you doctor will test not for the virus, but for the antibodies that your body produces to fight it.
After being exposed, it can take a few months before detectable traces of those antibodies are available. Meaning, basically, that if you contracted HIV last night, you wouldn't necessarily test positive tomorrow. But three months down the road you would.
Just keep getting tested every 3-6 months. If you test positive, test again immediately to confirm.