If your personal trainer did the test, what methodology did he use? My thoughts are that it's WAAAAAAY off.
I posted a 2 X 20 anaerobic threshold test, but I would still say it's better to be tested... let them take blood from you and monitor heart rate as they increase workload over time. Now that's accurate.
The more off you are, the less accurately you're able to train, and when you race, you'll never be at optimal training.
Koffee