From my own personal experience, I wouldn't call the process a "test" with your child. A lot of IQ testing is games. I would tell your son that he'll be asked to do some very easy things, as well as some things he might not be ready for. Encourage him to do his best, even if with the obvious. Sometimes GT kids will stumble over an easy question, because they rationalize internally that the question simply can't be that easy, and actually miss those points. Your son though can expect to have fun with the testing. Most kids enjoy that hour or so of one-on-one with a caring adult.
I would say that if your child is growing up in a medical family, and understands 'test' as in 'a thing doctors do to learn about a patient' then test is fine as long as the kid understands that there are no 'shots.' I like this because it encourages the child not to fool around. If the only 'tests' at your house are the school kind, where the amount of preparation a person puts in is presumed to influence their 'test score' then test is a bad word to use.
Something like, 'the doctor wants to see more about how you learn and help the school people know how to teach you' might work well. So much depends on the individual child.
Best Wishes,
Grinity
