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Thyroid UK
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Recent blood test results


My daughter has had the following blood test results and we would be grateful for any advice -

17.7.17 No Thyroid meds. on morning of test. Reg. dose day before was 1.5grains NDT + 25mcg T3 morning and 12.5mcg T3 evening.

Results = TSH - 0.35 ( 0.3 - 5.5 ) T4 - 5.4 ( 12 - 22 ) T3 - 4.8 ( 3.1 - 6.8 )

26.7.17 No thyroid meds. on morning of test. Day before - 1.5 grains NDT + 25 mcg T3 but ( unlike 17.7.17 ) no thyroid meds in evening.

Results = TSH - 0.21 T4 - 5.6 T3 - 4.5 ( all ranges as above )

The comparison between 17.7 and 26.7 is that there were no thyroid meds. on evening of 25.7. yet TSH is lower than on 17.7.

Any advice will be welcome.

3 Replies

Taking her hormone the evening before her test, won't have any effect on the TSH. It doesn't change that fast. Besides, the difference is negligeable. Were both tests done at exactly the same time of day?

The recommended time gap is 24 hours for T4, and 12 hours for T3. But, as you can't separate the T4 from the T3 in NDT, it's best to just leave 12 hours. :)


Hello Greygoose

Yes, both tests were done at the same time of day.

What is concerning is that, although the TSH is very low, the T4 is well below the range on both occasions. Have you any advice on that please?


She's taking NDT, which contains T3. The FT4 will be low when taking any T3, because the body only hangs on to what it needs. And, the TSH is low, because she's taking T3.

However, she is under-medicated, because the FT3 - the only important number - is below mid-range. Most people need it up the top of the range to feel well.


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