What is T3 testing?
T3 testing is to judge if high Iodine 131 absorption
rate is because of hypothyroid or goiter. The way is: After test Iodine
131 absorption rate, have T320ug, 3 times every day, last for 6 days
(or have thyroxine 60mg, 3 times every day, last for 8 days). Then test
Iodine 131 absorption rate again to compare the 2 results.
Repressive rate large than 50% is normal. It means
hypothyroid has normal adjustment relationship with pituitary. And
can be diagnose
not to have hypothyroid. Repressive rate low than
25% is less of restrain, can be diagnose to be hypothyroid. Repressive
rate between 25% and
50% is partially restrained. It can be diagnose to
doubtful hypothyroid, and need to be analyzed with other figures.
This test is very meaningful to hypothyroid and goiter. The Iodine
131 absorption rate for both of them can high than the normal range,
but the repressive rate will be different. Hypothyroid is less of restrain
while goiter is normal.
The key feature of Graves is do not have clinic hypothyroid behaviour
and one goggle-eyed or both goggle-eyed. The serum thyroid incretion
is normal. But pituitary-hypothyroid adjustment is abnormal. The Iodine
131 absorption rate is similar with hypothyroid. At this moment, The
clinic applied value is limited. It has been replaced by the high sensitive
TSH testing. And for pregnancy and old man and cardiac muscle bloodless
are not suitable for have T3 and T4, and forbid to have this testing.
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