Typically, anything over 35% at 24 hours is considered elevated, but the pattern of uptake is also an important element of the test. The raw percentage doesn’t always translate to thyroid hormone levels (in other words, your percentage may be slightly elevated, but your thyroid hormone levels may be WAY out of range, or vice versa). The uptake is generally used to confirm a Graves’ diagnosis (using both elements of the results, percentage and uptake pattern), and also to give the doctor some idea of the dose of RAI that would be required (if that’s what you want to do). In your case, your thyroid has taken up 45% of the iodine you ingested 24 hours ago, so let’s say the doctor wants your thyroid to take up 5 millicuries for RAI treatment (randomly chosen number, I know NOTHING about the reasons behind numbers for dosing) ~ they’d need to give you about 11 millicuries, because 65% of the dose would NOT be taken up.
