Question: 

A question we get all the time from patients and podcast listeners is if they should take their thyroid medication before a blood test.

Short Answer: 

There is not a simple answer to this question. It depends on the patient and their situation. For new patients, we typically want them to take their medication in the morning 3 to 6 hours before a blood test. This is especially true if we have made a recent medication change. If a patient skips their medication the morning of the blood test, it is harder to determine dosing adjustments. The longer someone has been on thyroid medication, the more likely we are to have them skip taking the medication the morning of a blood test.

PYHP 092 Full Transcript: 

Download PYHP 092 Transcript

Dr. Maki: Hello everyone. Thank you for joining us for another episode of the Progress Your Health podcast. I am Dr. Maki. 

Dr. Davidson: And I am Dr. Davidson. 

Dr. Maki: How you doing this morning? 

Dr. Davidson: I am doing very well. How are you doing this morning? 

Dr. Maki: Well, the skies are blue. The birds are out. Looks like it is going to be another beautiful day. 

Dr. Davidson: I look forward to it. It is what, spring in Washington. And even though, it does, it is Washington State it does rain here. But at least the you know; everything is green, and we do get some beautiful days. 

Dr. Maki: Yes. We certainly do. Now, granting the summer, people that are not familiar in summertime, there were hardly rains at all. June, July, August, September, does not rain hardly much. It gets kind of dry. But certainly, the spring, the fall, the winter, it makes up for those months that it does not rain for sure. Okay. So, this one is a situation that comes up all the time, for existing patients, for new patients, for questions we get from listeners and readers, the timing of thyroid medication and blood testing. Some say to take it in the morning, some say to take it the day before, and skip it that morning. There is, like I said, there is, you know, there is a couple of opinions and how that is supposed to be done or what say you? 

Dr. Davidson: I would say both. 

Dr. Maki: Yes. So, you would say that both are right. 

Dr. Davidson: Yes. When somebody asks, should I take my thyroid the morning of the blood test, there are times when I say yes, and there are times when I say no. You know, it really depends on how we are going to monitor it now. We are very specific when we monitor thyroid levels. Specifically, we will do the thyroid stimulating hormone, the TSH, the free T4 in the free T3. You know, we want to, you know, those are kind of like my nitty-gritty. I mean, then you can do a reverse T3 and a few others but really, you know, the free T3 is super important. A lot of conventional doctors do not always test the fre