Thyroid Disorders Community
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Take meds or not before testing

Are you supposed to skip your thyroid meds the day of testing? I have added a T3 med to my T4 and had a test after 8 weeks. My FT3 was 3.5 (up from 2.4), FT4 was1.46 (up from 1.26), and TSH was 0.10 (down from 1.7 where it has been for years. No one said not to take my meds before the test, so I took them.  My PCP kept me on 0.88 T4 but tried to get me to skip the T3 two  days/week.  I had a retest in 8 weeks but I read that you are not supposed to take your meds before the test, so I didn't. This time FT3 was 2.4 (down again), FT4 was 1.57 (up more this time), and TSH was 0.11 (about the same, still low). I do not feel hyper, am not losing weight, still tired, blood pressure normal 120/80, but I don't know how I should adjust the meds. Also,went from osteopenia to osteoporosis. I am 60,10 years post menopausal. I take D3 with K2, magnesium, but no calcium (my blood calcium is high). HELP!
3 Responses
Avatar universal
As far as T4 meds is concerned, what's most important is consistency.  Either always take it or never take it.  T3 meds is a different story.  because of the fast acting nature of T3, you don't want to take it before the draw, or it can inflate your result (as you saw in the first labs you posted above).

What are the reference ranges on your FT3 and FT4?

T3 meds tend to suppress TSH.  Once on T3, TSH often becomes useless.

Your doctor doesn't seem to be a very good thyroid doctor.  You can't adjust T3 meds like that (skip two days a week) like you can T4 meds.  T3 is so fast acting that most people split their dose into two half doses, one in the morning with T4, the other late morning to early afternoon.  Are you splitting?

Once I see the reference ranges, I'll comment on where you should go.
Avatar universal
Thank you goolara for responding!  This last FT3 (no meds before test) of 2.4 is low (range is 2.3-4.2), FT4 (no meds that AM) of 1.57 (range is 0.89-1.76).  I take .088mg synthroid and 5mcg cytomel in AM. Was never told to split the T3. It is the lowest dose.  Should I take a second one later in the day? Thank you for your help!
Avatar universal
Your FT4 is on the high side, 78% of range, and the target for FT4 is about 50% of range.  So, I'd be very leery of increasing your T3 dose without dropping your T4 dose a bit.  Have you considered cutting your 5 mcg tablet in half and taking half in the morning with your T4 and half later in the day?  That might help.  I do think you could use the increase in T3, but not without reducing T4.  You also might consider going to 7.5 mcg before going straight to 10 mcg.  Now that your FT3 is back down again, perhaps your doctor would be more open to one of those possibilities now?  
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