I didn't say anything to my daughter when they tested her. The kids have so many "tests" anyway that it didn't seem out of place to her at all. If she hadn't qualified after the testing, I wouldn't have had to tell her that she didn't make it 'cause she never knew what they were testing for.
My daughter never even pays attention to those kinds of things if they aren't made a big deal of in the process. I mean, she was so stressed about the stupid TAKS test 'cause all the teachers were pushing how important it was for them to pass. We had to sit her down and just remind her how fantastic she was in reading at school and that we didn't have a worry in the world about her passing. We knew if she just took her time and answered the questions to the best of her ability, she would do just fine. Of course she aced it. I asked her about it after we found out she got all the answers correct and she even mentioned that she remembered us talking about taking her time and she slowed down and didn't worry about it any more.
I think elementary school is too soon to have stresses about testing or qualifying for special programs and such. If they qualify, that's great. Why stress them with the "why's" at such a young age? That's my opinion anyway.