My son is 8yrs old in 2nd grade, he has been referred to the gifted and talented program at his school. He has taken the NNAT and scored in the 99 percentile, and the KBIT and scored in the 99.5 percentile. I know that these scores are good, but how good and does he need further testing. What would his IQ be?

Read http://www.hoagiesgifted.org/iq_varies.htm

and
http://en.wikipedia.org/wiki/NNAT

Although this is outdated,take a look at http://alpha.fdu.edu/psychology/kbitwisc.htm
to get some idea of how folks go about answering the question - does the KBIT screener correlate to an IQ test?

Then there is the question of 'How good are IQ tests at measuring IQ when the subject is unusually gifted?' It has been considered that around 99.8 most tests start to lose meaning.

Are these scores good? That sort of depends on what you were expecting? Depending on the local expectations, folks at the 90% can start feeling like they are always going to be the smartest folks in the room. On the other hand, I'll bet you've heard plenty of stories about kids feeling mighty stupid when they get to places like MIT. There isn't any 'approved' definition of gifted, or of any of the levels of giftedness.

If you can say more about what you might hope to gain by testing, we can ask better questions to help you think about 'what's it worth to ya?'

Love and More Love and Welcome!
Grinity

I was surprised by the test scores. He is very smart, but as our oldest we were thinking that he was average because we didn't have anything to compare it to. He was reading at 3, math at 4, and all his teachers said he was very bright. Now after the school testing and admission into the gifted program for next year, I'm worried that I'm not doing enough to challenge him. I didn't know if more testing would help us or if I should just leave well enough alone. Any help on what to do with him would be awesome.

There is a lot of material at khanacademy.org that you can do with your child at his own pace. My son loves it. He especially likes the badges and the graph of his progress. Keep it fun. Let him explore what he likes for only as long as he is interested.