Our school did the WJ-III achievement test with our DS then 5 yrs 9 months, because they were building a portfolio for skipping him over kindergarten into first grade. They had to norm it as kindergarten-9th month (end of K) because it doesn't have anything lower grade-wise, but it let them norm it age-wise as 5.9.

Those scores and a collection of his math writings and drawings were enough for DYS. We did not have an IQ test for him, and they didn't ask for it.