I'm not familiar with any type of screening that gives the types of numbers you were given, but I'd be willing to bet that, with a PG older sibling and the signs of giftedness you mention, he is gifted. I wouldn't keep him out of a school that you think would be a good fit b/c you're unsure whether he'll qualify on IQ later. It sounds like the odds are heavily in his favor that he will.

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