hypothyroid people: do you take your thyroid meds before lab testing?

[alice111]

hi guys,
asking all hypothyroiders: when you do you lab testing (for tsh,t3 t4) do you take your thyroid meds before testing? i know sttm seems to have some contraindicating info on this.. just wondering what most people do because my lab test will have a HUGE difference if i take before vs if i dont
thanks

 

[*GG*]

Pretty certain my Dr tells me not to take it. Why don't you ask the doctor? Just to be certain!

GG

 

[Old Bones]

I consistently do not take my thyroid medication the morning of my thyroid tests. This means the previous day's medication was taken at least 24 hours before the blood draw.

 

[barbc56]

Wouldn't your Doctor want to see your blood levels on the medication to decide if it needs to be adjusted? Is that why you are getting the tests?

My Doctor has me take my medication the day of the test, however, your circumstance might be different.

There are some blood tests where you fast, so that kind of contradicts what I said above.

There used, or maybe still is, the same issue with a sleep study. For mine, I took my usual medications except told not to take the neuvigil eight hours before the test which I don't do anyway. Maybe some tests are repeated, with and without taking your meds.?

As others are saying, check with your doctor. Let us know. I'm curious about this.

ETA
Does the lab request have this information? I also get written instructions whether or not to take my medication but this may be specific to my medical clinic.

 

[*GG*]

Wouldn't your Doctor want to see your blood levels on the medication to decide if it needs to be adjusted? Is that why you are getting the tests?

My Doctor has me take my medication the day of the test, however, your circumstance might be different.

There are some blood tests where you fast, so that kind of contradicts what I said above.

Maybe it depends on the Thyroid drug? Synthetic vs Natural? I take the Natural stuff daily. Figuring you take it daily because it is not long lasting? So not taking the day of blood draw would mean lower level in blood, so you need the medicine?

If you had taken the medicine, perhaps you might be over the target value. So then they don't know how much you really need to have a good amount in your system?

GG

 

[barbc56]

Maybe it depends on the Thyroid drug

Good point as I think it does make a difference which medication you are taking as they are metabolized differently.

I don't want to get into the whole synthroid vs. armour debate as that's a personal choice. But it's important for a physician to know which medication you are taking if getting their thyroid medications from another physician.

Just another factor to be considered when the results of the blood test are known. I have no idea if this really makes a difference whether you take a medication the day you get a blood test.

 

[adelheid55]

The GP says not to take it before the blood test. The endocrinologist says to take it.

 

[Gingergrrl]

The first two years I took it the morning of the test (Armour Thyroid) b/c I did not realize that I was not supposed to. Now I skip it before the test, per my doctor, but am not sure if it is a huge deal either way since I take a very low dose and my numbers are normal now either way. I would ask your doctor what he or she prefers.

 

[Old Bones]

Wouldn't your Doctor want to see your blood levels on the medication to decide if it needs to be adjusted? Is that why you are getting the tests?

I did a "gluten challenge" during a period of time when I was having monthly thyroid tests. From one month's test to the next, my thyroid numbers changed so dramatically, it appeared the dose of my thyroid medication would have to be increased by several "steps". The following month, having returned to a gluten-free diet, my thyroid numbers were again optimal for me. All tests were done after not having taken my thyroid medication for slightly more than 24 hours. So, it appears it is not necessary to see blood levels while on the medication to decide if it needs to be adjusted.

Perhaps what is important (based on the above posts) is that patients are consistent in either taking, or not taking, their medication before thyroid blood tests.

 

[barbc56]

Perhaps what is important (based on the above posts) is that patients are consistent in either taking, or not taking, their medication before thyroid blood tests

That makes a whole lot of sense as others are getting varying answers from their doctors. Maybe, when it comes to testing your thyroid levels it's the relative change.

I'm still curious why some blood tests need you to fast to get an accurate result. There must be some reasoning/mechanism behind it. I have no clue what that would be but I'm not in the medical profession.

This is all rather fascinating.

 

[alice111]

Hah I don't know if I'm now more confused than before..

As for asking my doctor, I don't think she really knows..
I agree that synthroid makes a big difference, as it has a much longer half life, but I'm currently on all desiccated.

I guess what I find confusing is how drastic the difference is if I take it vs if I don't.. If I don't take it my tsh is waaaay high out of range, and the t3 and t4 are way low out of range.. I guess cus I have hashis I do t think my body can even make thyroid hormone anymore?

 

[*GG*]

I guess what I find confusing is how drastic the difference is if I take it vs if I don't.. If I don't take it my tsh is waaaay high out of range, and the t3 and t4 are way low out of range.. I guess cus I have hashis I do t think my body can even make thyroid hormone anymore?

So does taking the medicine Drastically make a difference on how you feel? Mine doesn't!

GG

 

[alice111]

@ggingues no it doesn't! I guess it's just. Question of whether or not I'm on enough meds in general

 

[Eeyore]

I always take my thyroid meds. My endo wants to see what my TSH is when I am taking the med at the normal dose so he knows whether or not to increase/lower the dose. He's not interested in what my TSH would be off meds (and T4 has a long half life anyways - so skipping a day won't have a big an effect as you'd think - also, the TSH scale is logarithmic).

You should probably ask your doc though - but that is what my endo requires, and he is a thyroid specialist.

 

[Oci]

I always take my thyroid meds. My endo wants to see what my TSH is when I am taking the med at the normal dose so he knows whether or not to increase/lower the dose. He's not interested in what my TSH would be off meds (and T4 has a long half life anyways - so skipping a day won't have a big an effect as you'd think - also, the TSH scale is logarithmic).

You should probably ask your doc though - but that is what my endo requires, and he is a thyroid specialist.

My doctor insists that I take the morning dose and do the test 4 1/2 hours later. He says that the drug peaks at 4 /12 hours and he wants to see the high point. I take natural thyroid.

 

[Eeyore]

My doctor insists that I take the morning dose and do the test 4 1/2 hours later. He says that the drug peaks at 4 /12 hours and he wants to see the high point. I take natural thyroid.

My doctor isn't so strict about it but that approach makes a lot of sense and gives nice consistent results.

 

[JAH]

I have asked this question to 3 doctors.

Doc #1: don't take it
Doc #2 take it
Doc #3 it doesn't matter

I would do what you normally do. Good luck!

JAH