It has nothing whatsoever to do with the grades you get in school. Because it's totally confidential, it's not going to be stamped on your transcript or be reported to the college boards.
By the way, did you know there's a lot of disagreement about IQ tests in general? Some experts say the IQ number may not even have all that much to do with intelligence (Gould, 1981; Siegel, 1999). That's because a lot of things affect how we p