McCall McPherson, PA at Modern Thyroid Clinic, explains how to prepare for thyroid blood tests. You don't need to fast. For desiccated thyroid, wait 3-4 hours after your morning dose. For T3 medications like Cytomel, get labs drawn about 2 hours after taking it to catch peak levels.
Questions this video answers
No. Fasting is generally not required; you may eat and drink (including coffee and water).
Take your morning dose and have labs drawn 3–4 hours after dosing (or 3–4 hours after an equal afternoon dose).
Aim to have labs drawn about 2 hours after dosing to capture peak T3 levels.
Timing is less critical; avoid having labs drawn within 1–2 hours after dosing to be safe, but minor fluctuations are usually insignificant.
Chapters
Hey, I'm McCall McPherson from Modern Thyroid Clinic. I'm the PA and co founder here. Today we're going to talk about your lab day kind of protocol with your medication and how to roll in to get your labs done. But before I'm just going to recap on the actual labs that you need to have drawn. If you want further detail, you can check out our previous video about labs, but here are the ones you need. Write those down. And so we want to think about this in a few different ways for different medications, but kind of big picture items are frequently right. Most common question do I need to fast? The answer is no. If your doctor tells you you need to fast or the nurse tells you you need to fast, in fact, you don't need to fast. They're just assuming that because they don't know the real answer. So it's better safe than sorry. So eat, drink, be merry the morning of. If you are on, well, what other questions do you have? You can drink coffee, you can drink water. None of that will affect your thyroid numbers at all. Your labs might be affected somewhat if you don't eat and you take them on a very, very empty stomach. If you have active thyroid medications like natural desiccated thyroid or Cytomel, but let's break it down medication by medication. So if you're on desiccated thyroid, so that would be on Armour, Nature throid, WP thyroid, Westeroid, NP throid or NP thyroid, if you are on those, I want you to take your medication the morning of your labs and actually go three to four hours after you take it. And this is because your medication will be metabolized much more quickly than if it's a T4 based medication. So for all of those desiccated thyroid, you're going to go three to four hours in. If you have an afternoon dose of thyroid medication and it's equal to the morning dose, you can also go in the afternoon three to four hours after you take your med, which is kind of weird because that would put you at like 7 or 8pm for most people. Not handy if you are on cytomel or leothyrene. So so basically a T3 based medication. These medications get metabolized really, really quickly unless they're compounded to be sustained release. So that being said, you would take that medication and really go around two hours after you take it. When we do things this way with medications that have T3, what we're doing is purposefully catching your labs at their peak value. So when your T3 would be at its highest, because that's my biggest concern. And most people that are familiar with thyroid treatment, we don't want your T3 to get too high. So if we know what it is at its peak, we can know with precision how far we can push your treatment in the future. And we don't have to worry about not knowing that if you are taking T formets. So these are things like Synthroid, Levothyroxine, Unithroid, Tyrocent. These medications are metabolized really, really slowly. That's why people don't really feel a difference for weeks after they start taking them. So it's less significant when you take these medications. There are some people that say you need to avoid going an hour or two after you take them. And I say, sure, to be on the safe side, you can do that. But for the most part, with people on T4 medications, the fluctuations of their hormones are so minimal that it doesn't really matter. I think that's just about it for protocol for lab day. If you want more information about your labs or your lab values, check out our courses below.
