when is best time to do labs?

[aaamommy27]

I take Synthroid first thing in morning and Cytomel a few hours later. When should I do labs to check thyroid?
Before any pills? Or does it matter if I take Synthroid?

[aaamommy27]

So, like I said that my labs were done at 3pm and after taking my Synthroid and Cytomel:

Free T4    1.32    (.82-1.77)
Free T3    3.6      (2.0-4.4)
TSH      .425 L    (.45-4.5)

This is the best my Free T3 has ever looked. Of course my doc freaked out because my TSH is low. He wants to lower Synthroid from 137 to 125. I do have palpatations and insomnia, but I am also gaining weight like crazy!! I have gained 15 lbs since Christmas.

Any thoughts would help!!! Should I repeat labs in a.m. before lowering meds?

[aaamommy27]

I do understand that, but when I have upped Cytomel in the past I get heart palpatations.
I have been getting them again lately and all my Frees are in "normal" range. They want me to lower Synthroid based on the TSH. The only reason I am willing to is because of racey heart.

[gimel]

Study data that I have run across showed that TSH correlated mostly with FT4, and not so much with FT3, and imperceptibly with Total T3 .  Some other study that I have seen said that when a patient is taking thyroid meds, TSH is even more unreliable as an indicator than before meds.  At no time does it seem that TSH is adequate as a diagnostic by which to dose a thyroid patient.  At best TSH is only an indicator, to be considered along with more important indicators such as symptoms and FT3 and FT4.

[aaamommy27]

I had my blood drawn after 3 pm the other day and my TSH is 0.3. It went down quite a bit from last time. Does T3 affect your TSH or just the Free T3??

[gimel]

Best to have blood drawn before taking meds with T3, because it is so fast acting.  With T4 being so much slower, it really is not a problem.