Well, most likely you will have some air come out as you try to check it. The better you are at keeping your hand fast and steady, the less air you will let out. The best is when you only hear the air come out for only a few milliseconds, but either way it doesn't matter too much. Use either a digital or dial gauge to check the pressure. I don't trust those stick things.

Also, I think it's better to go by the recommended psi on the tire itself strykernyc.