[MENTION=8603]Eventhorizon[/MENTION] , According to online tests I am one, and according to simular online tests I am some type of elemental dragon or a knight...

but it is like hush said I think it is unrealistic to believe an empath will aways know what you're feeling just because some online tests peg them for one.
Besides, do you honestly believe someone when they come up to you and say: "I'm an empath and I know what you're feeling, and I just had to talk to you" ?
Like 99.99% of the time the first thought someone will have is probably something like "wtf some crazy person is pretending to know me x)".
Empaths are not some kind of psychics contrary to lots of peoples wishfull thinking. I am not sure what even brought that notion into peoples heads.
A lot of INFJ's do believe they are empaths but their actions tend to prove that most of them are a lot less empathic then they imagine themselves to be ;p
Plenty of us are sympathetic as hell but only have the barest of grains of empathy more then your avarage person and they will claim to be empathic ;p
If people are really empaths then I doubt they will need to tell you that or phrase their sentences in ways to suggest that they believe they are.
It sounds a lot more like they're trying to convince themselves as much as they're trying to convince you.
And if someone really is an empath, then you will make that conclusion yourself after a passage of time,
and your own thoughts and feelings on a matter are a lot more reliable then someone spelling their self proclaimed awesomeness out for you.
But hey that's just my opinion ^^