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The WAIS-IV, WJ-IV COG, and SBV are all normed for adults, generating deviation IQs up to or approaching about 160 (+4 SDs). Out of pocket cost starts at about $400 for IQ only (depending on your region), and runs through multiple thousands for a full neuropsych.

Some of the high-IQ societies referenced above by indigo also offer their own qualification tests, which are generally closer to $100 ($40 for Mensa).

...pronounced like the long vowel and first letter of the alphabet...