Thyroid UK
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Blood results

I have just received my blood results and would appreciate some help in interpreting them.

TSH 0.06 (0.27 - 4.2)

free T4 23.4 (12.0 - 22.0)

free t3 5.8 (3.1 - 6.8).

I had my blood taken at 10.30am, had eaten breakfast and taken my 50mg of Levothryroxine.

My TSH in June was 0.95 (0.27 - 4.2)

I am awaiting my reverse T3 results and am in the middle of a changeover from 50mg Levothryoxine to Nature Throid half a grain.

Any advice would be appreciated.

7 Replies

Nik, Thyroid medication should be taken after your blood test. Levothyroxine (T4) peaks 2-6 hours after ingestion so your blood test reveals the T4 peak rather than your normal serum levels. This will explain your low TSH and elevated FT4. Your June TSH looks to be in the right area.

1/2 grain NatureThroid is roughly equivalent to 37.5mcg T4 but you are right to take it slowly until 8 days after your last Levothyroxine tablet to avoid being overmedicated. Stay on 1/2 grain for 10/14 days before increasing by 1/4 grain increments every 2 weeks until your symptoms are resolved.


Thanks Clutter. I remembered I should not take meds or food prior to the test on my way to the appointment! Could I just check, as I was not on any T3 medication at the time, this would be my true T3 result? I am also awaiting my reverse T3 so again, would this be affected as I had take Levothyroxine? Thanks


Nik, I really don't know whether T3 or rT3 will have been affected.


I would think not. It takes time for the T4 to be converted into T3. But I'm not an expert. lol


It would be helpful to know if your doctor advised you to change over to NT.

If they did and you live in the UK, please let Louise know who by email -

thanks J :D

please everyone sign the petition


I had to go private to see a doctor who practices functional medicine due to the shoddy response from my GP. The FM doctor was on the Thyroid UK list.


thanks :D


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