Timing of testing thyroid hormone levels

[Marco N Cognito]

The consensus of opinion from most practitioners is to NOT take your med for at least 7 hours prior to lab draw. I had always taken my morning dose about 2 hours before draws and likely received misleading serum levels until I recently changed to taking my last dose about 15 hours prior to the draw. I split my NDT in 2 doses, early a.m. and late afternoon. What has been the advice of everyone's doc and what were your results?

The Do's and Don'ts of Thyroid Lab Testing - Dr. Izabella Wentz

Are Thyroid Lab Tests Accurate if Testing Occurs 24 Hours After the Last Dose? – Thyroid Fact or Fiction?

 

[captain]

Instructions I always hear is to take your meds as you always do. Your first link talks about TSH and is incorrect. TSH doesn't change that fast and would still be suppressed even if you didn't take your med. It all goes back to treat the patiant and not the number. If your doctor can't do that find one that will.

 

[JimGainz]

I would recommend taking the meds as normal. I was skipping my normal morning dose of T3 and the doctor kept increasing my dose to get me high normal. This sent me Hyper big time. When I went back to the previous dose -except this time taking them before bloods - I was already at the very top
of the T3 range. It’s different from, let’s say Testosterone testing where you want to see the results at the lowest point. With thyroid - you want to see where you are on the meds with the normal dose. This is definitely true if you are taking T3 only. With T4 meds it may not matter.

 

[Marco N Cognito]

I would recommend taking the meds as normal. I was skipping my normal morning dose of T3 and the doctor kept increasing my dose to get me high normal. This sent me Hyper big time. When I went back to the previous dose -except this time taking them before bloods - I was already at the very top
of the T3 range. It’s different from, let’s say Testosterone testing where you want to see the results at the lowest point. With thyroid - you want to see where you are on the meds with the normal dose. This is definitely true if you are taking T3 only. With T4 meds it may not matter.

It's really very confusing isn't it? Most say you can only gauge true levels when you skip the morning dose on test day whereas others say to take your dose as usual and then draw (which is what I had always done up until the last few months). Maybe I should do both and then re-assess.

 

[Vince Carter]

Logically you would want to take your meds as usual in order to see how the meds are effecting your levels. If you don't take them you would just see presumably just return to your baseline numbers and as noted by JimGainz, Dr would just up your dose because it appears to not be working.

 

[Gianluca]

I was told by either Dr Crisler and Defy to take Thyroid before labs

 

[Vince]

I was told by either Dr Crisler and Defy to take Thyroid before labs

Here's an old thread of mine.

Take your thyroid meds before of after your Labs?

 

[Marco N Cognito]

It is the consensus of docs in the know and my own experience that taking combination or T3-only meds within 3-4h of testing will give us misleading results. Not so with T4 only meds.

 

[Gianluca]

ah, I'm now confused, I take combination of t4/t3, NP thyroid, and my FT3 level after a couple of hours is 4.5, so that actually is not an accurate measurement? beside, it is more important to focus on symptoms, which I still actually show some hypothyroidism symptoms

 

[Vince Carter]

as always facts vary depending on who you ask and want to believe.

 

[Marco N Cognito]

ah, I'm now confused, I take combination of t4/t3, NP thyroid, and my FT3 level after a couple of hours is 4.5, so that actually is not an accurate measurement? beside, it is more important to focus on symptoms, which I still actually show some hypothyroidism symptoms

I found this blog pretty informative:
Updated - The Top 5 Myths About Natural Desiccated Thyroid | Dr. Alan Christianson

The Role of Testing
If someone is on NDT, and a doctor runs a test like:

• TSH
• Free T3
• Free T4

In this case, the doctor might notice that T3 is too high. This will then lead them to believe that you need less, because of the fact that your ratio is too high.
The real problem here actually is not the ratio, but the timing of the testing itself.

Key Insight: If you take a blood test right after taking your NDT tablet, your TSH and Free T4 might remain normal, but it can make your Free T3 score look shockingly high. This is only a question of timing, and nothing more!

Testing Your Thyroid: The Definitive Guide to Optimal Ranges | Dr. Alan Christianson

What time of day do I test?
Do your blood tests first thing in the morning, before eating, and before taking your thyroid medication – you will want to take your daily dose of medication immediately after your tests.

Common Issues with Thyroid Testing
These are some of the common issues we might encounter when testing our thyroid gland:

• T3 Too High – it is typically because you took your thyroid medication before an examination. Overall, it speaks to the absorption cycle of T3 in your body, and this could lead to well-intending doctors prescribing improper medications.
• TSH Too Low – It’s a bit controversial, but it’s a tough thing to understand. There might have been some who work on a too low TSH, but it’s a numbers game. A low TSH is fine for some, but not fine for others. It’s a risk factor, and so it’s worth understanding. Toxicology and adrenal function are important “root causes” to identify when this is the case.
• Erratic Antibody Levels – thyroid antibodies are good to confirm diagnoses, but they don’t rule it out when they aren’t around. They’re also important to note for fertility (6). High antibodies, four digits and above, can cause issues. Otherwise, there probably isn’t a lot to say about your problems. They can go up and down randomly, so keep that in mind and do not worry too much.
• TSH Drift – Your TSH isn’t going to level out immediately. It can take about three months for your TSH to level out after you have made a change in your lifestyle. If it’s moving down, it might be enough to say that it was the intent that is wanted, but it won’t reach that state until enough time has passed. Patience is key, so make sure you are keeping an eye on it’s steadiness.

When should I test?
A schedule for testing looks a little something like this:

• Full panel of testing begins to understand your body’s baseline for health.
• After treatment has started, there will be focused re-tests that are dialed in specifically on treatment.
• After your body has reached a steady state, there are tests once a quarter (one or two).
• Post-program, you will be looking at tests twice a year.

You may also enjoy tests approximately four weeks after dosage changes. As well, any time that you have unusual symptoms where you think your thyroid might be the culprit – this is going to circle back to the importance of self-exams and your thyroid health!

 

[Gianluca]

I found this blog pretty informative:
Updated - The Top 5 Myths About Natural Desiccated Thyroid | Dr. Alan Christianson

The Role of Testing
If someone is on NDT, and a doctor runs a test like:

• TSH
• Free T3
• Free T4

In this case, the doctor might notice that T3 is too high. This will then lead them to believe that you need less, because of the fact that your ratio is too high.
The real problem here actually is not the ratio, but the timing of the testing itself.

Key Insight: If you take a blood test right after taking your NDT tablet, your TSH and Free T4 might remain normal, but it can make your Free T3 score look shockingly high. This is only a question of timing, and nothing more!

Testing Your Thyroid: The Definitive Guide to Optimal Ranges | Dr. Alan Christianson

What time of day do I test?
Do your blood tests first thing in the morning, before eating, and before taking your thyroid medication – you will want to take your daily dose of medication immediately after your tests.

Common Issues with Thyroid Testing
These are some of the common issues we might encounter when testing our thyroid gland:

• T3 Too High – it is typically because you took your thyroid medication before an examination. Overall, it speaks to the absorption cycle of T3 in your body, and this could lead to well-intending doctors prescribing improper medications.
• TSH Too Low – It’s a bit controversial, but it’s a tough thing to understand. There might have been some who work on a too low TSH, but it’s a numbers game. A low TSH is fine for some, but not fine for others. It’s a risk factor, and so it’s worth understanding. Toxicology and adrenal function are important “root causes” to identify when this is the case.
• Erratic Antibody Levels – thyroid antibodies are good to confirm diagnoses, but they don’t rule it out when they aren’t around. They’re also important to note for fertility (6). High antibodies, four digits and above, can cause issues. Otherwise, there probably isn’t a lot to say about your problems. They can go up and down randomly, so keep that in mind and do not worry too much.
• TSH Drift – Your TSH isn’t going to level out immediately. It can take about three months for your TSH to level out after you have made a change in your lifestyle. If it’s moving down, it might be enough to say that it was the intent that is wanted, but it won’t reach that state until enough time has passed. Patience is key, so make sure you are keeping an eye on it’s steadiness.

When should I test?
A schedule for testing looks a little something like this:

• Full panel of testing begins to understand your body’s baseline for health.
• After treatment has started, there will be focused re-tests that are dialed in specifically on treatment.
• After your body has reached a steady state, there are tests once a quarter (one or two).
• Post-program, you will be looking at tests twice a year.

You may also enjoy tests approximately four weeks after dosage changes. As well, any time that you have unusual symptoms where you think your thyroid might be the culprit – this is going to circle back to the importance of self-exams and your thyroid health!

I don't get it, if you take your Thyroid and after a few hours you are at optimal ranges, that is it. Thyroid is taken everyday, so if you would measure blood on empty stomach, it would be like you would not take it, then giving you a false measurement?

then, if someone needs to be above "optimal ranges" to feel good, that is another discussion. Beside, we should always focus on symptoms, not numbers.