Should thyroid med be taken before morning lab tests

[5thave]

All these times I have lab tests done I usually take my thyroid med in the morning when I wake up. Am I doing this correctly? Are they measuring the dose that you currently have in your system and how it is responding? Seems that if you did not take it you would be very low because then it would have been 24 hrs since your last dose. Can anyone answer these questions? Thanks

[5thave]

Thanks for this info. Wonder why the doctor never told me that. Do they just assume everyone knows you shouldn't take your meds first? I was taking them figuring the blood draw would measure me on the meds  and  that would be the current level. Well now I know better thanks again!

[kitty9309]

The TSH and free t3 are not affected by taking the meds before the blood draw, but the free t4 is.

The free t4 result will be increased by 20% for 4 hours after taking a t4 containing med and not return to baseline for 9 hours after ingestion.

Also, as AR said, the TSH reaches a peak overnight into the early mornong hours and is at it's lowest in the afternoon.

(Thanks AR!)

[laura1967]

Both my doctors said to make sure you take your thyroid meds AFTER you draw or it can cause false numbers. I take mine with me and take when i get back in my truck at lab after they have taken my blood. Then I enjoy my coffee.  :) :)

[5thave]

So all these years I have been doing it wrong. Even doing it wrong with thyroid in me before lab tests my numbers are low. Well that may explain things. No wonder I never feel yippy skippy. They probably dose me too low.

I am now on 2.5 grain Armour how high does it go. I started at 1 grain 2 years ago.

Thanks for all your input.

[lilypad300]

thanks for posting this question!!

i've been going round and round with what I should do.
i go tomorrow for blood work for TSH and my calcium levels.

I take my synthroid (.175) at 6:00am
and my 1st dose of calcium at 10:00am  (I takeit 4 x's a day)

when should I get my blood work done to get the most accurate results.
the lab is open from 7am to 4pm.

thanks!!

[AR-10]

I take my thyroid med in the morning and have a blood draw about ten.

That's the wrong way to do it.
It will elevate your Free T4.

You should get your blood drawn early in the day and then take your thyroid med. As a side note, due to the circadian rhythm of your body, your TSH is highest in the early morning.

So...what do you want to have a tad high? Your TSH, or your Free T4?

Isn't this fun?

Kitty works in a lab and she says do it in the morning before taking meds. Do it that way if you can. She knows what she's talking about.