Blood Drug Testing

Thyroid testing -- should I take my medication on the morning of a thyroid blood test?

My doctor says it's OK to take the medication and I don't need to fast. My mother's doctor tells her the exact opposite. These are strictly thyroid tests -- not looking for fasting glucose or cholesterol levels.

Public Comments

1. Listen to your doctor. They may not be the exact same tests and they definitely aren't on the same people.
2. i would listen to your doctor. my moms doctor may be telling your mom that for her tests. if you are having your thyroid levels tested you want the normal amout of medication in your system.
3. Most definitely. Your doctor is 100% correct. You should continue taking your thyroid medicine that day like you always do. When you get your thyroid test, they are seeing if your hormones are within normal limits on the amout of medicine you're on. If not, they will adjust the dosage (mg) amount of your medication. (And, it's very important to be on this medicine, probably the rest of your life, because there are serious side effects if you aren't...most of them silent. You can search the web for more info on that if you're interested.)
4. your doctor is 1oo% right...your thyroid tests are probably made to see whether u r responding well 2 ur dose,,so as 2 adjust it if there is an icrease or decrease in it. so continue 2 use ur medication and it has nothing 2 do with fasting.
5. No, do not take your thyroid medication prior to testing. Test first, then pop your medication. Also, make sure to test first thing in the morning while TSH is near its high point. Link below about testing and taking morning meds. Link states "Blood Tests1 If you take thyroid supplement medication on the day of your blood test, you should wait until after the blood has been drawn so as to avoid any test interference. Once the blood has been drawn, you may take that day’s dose and return to your regular dosing schedule."
6. Your thyroid medicine should always be taken in the morning, before you eat. If the only test you are having done is the TSH for dosing information, just take your medicine as usual. If you go to the site http://www.armourthyroid.com/hypothyroidism/diagnosis.html it will tell you not to take your meds first as it may interfere with the test... that is a general statement meant to apply to all of the tests, where some of them might be effected. I take Synthroid and have for years... getting my levels checked regularly. My doctor always tells me to take my meds as I normally do, just as your doctor told you. If you don't take it normally, it could skew the results that will determine your dosage.