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Problems on Diseccated Thyroid

Hi everyone,

I had a question about my lab work. I am at a real loss, and so is my doctor. I have been to endocrinologists and I am only 17 years old. I have had thyroid problems for years now, both hypothyroid and hyperthyroid. Before starting Naturethroid, my lab work was as followed.

TSH : 2.6 (.3-5)
FT4 : .8 (.8-1.7)
FT3 : 3.0 (2.3-4.2)

So, after this, my doctor started me on Naturethroid. I started on 25mcg Naturethroid for a slightly elevated TSH, and low Ft4. My labwork was as followed.

TSH : 1.9 (.3-5)
FT4 : 1.1 (.9-1.6)

No FT3 this time. Things were looking good, but my doctor moved me up. I was raised dose to 75mcg Naturethroid. My labwork was as followed.

TSH : .3 (.4-4)
FT4 : .7 (.6-1.7)

Ok, so what's up? Why did my FT4 drop so low? The doctor said my TSH means I'm HYPERthyroid, but my FT4 indicates HYPO. Why is this? Is it because my FT3 is high? No luck on getting a request for it so far, any thoughts? All my symptoms point towards hypothyroid. Help would be greatly appreciated.
Best Answer
Avatar universal
I agree with Red's paste about TSH.  Once on thyroid meds, especially it seems meds with T3 in them, TSH can become totally unreliable and can no longer be used to determine thyroid status.

In the first set of labs you post (FT3=3.0, FT4= 0.8), were you on any thyroid meds at the time?  If so, which and what dose?

You are on meds with T3 in them.  Your doctor MUST test FT3 every time you have labs.  We have no idea what your FT3 levels are doing.
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798555 tn?1292787551
Not unusual.

Dessicated thyroid has a higher ratio of T3 in it than humans do. All the brands of dessicated usually makes labs that have FT near the top with FT4 near the bottom. Nature Throid in particular makes this more apparent than some of the other brands of dessicated.

This is my best guess based on others and my own experience: Once on dessicated its the high FT 3 that makes the TSH drop so much. I bet your FT3 is near the top of the range - you need this tested. Your pituitary sees the high T3 so its saying "no more thyroid hormone" by dropping the TSH. When T3 is high , it seems T4 takes the back seat of prioirties as far as the pituitary goes.

I've been on N Throid in the past, as well as four other dessicated manufactures.
Helpful - 0
Avatar universal
One question that comes to mind is when are you getting your blood drawn and is it before or after you've taken your medication.

T3 has a very short half life measured in hours.  T4 on the other hand takes weeks.  So if you have taken your medication as little as an hour or so prior to the blood being drawn, it WILL show a higher level of T3 than is averaged in you blood.

it is best to try to get the blood drawn under about identical conditions as possible and ideally if possible to get the blood drawn before you take a medicine containing T3.

I'm not saying you did anything wrong. Just the possibility that the timing can play a part in this.

Another question is not so much about the levels. But rather probably the most important question that doesn't seem to be addressed here.  And that is;

How are you feeling?  What symptoms are you having?  Are they getting better or worse?
Helpful - 0
Avatar universal
Correct me if I'm wrong, but this is the first FT3 you've had since being on NT???

I'm a bit confused.  Above (in your original post), you said you were on "...75mcg Naturethroid. My labwork was as followed.

TSH : .3 (.4-4)
FT4 : .7 (.6-1.7)"

I assume you meant your were on 75 mg, which is 1.25 grains.

In the post immediately above, you say that your dose was raised to "...3/4 a grain (45 mg), these are the results.

TSH : .7 (.3-3)
FT4 : .7 (.8-1.8)
FT3 : 2.6 (2.3-4.2)"

3/4 of a grain would be 45 mg, less than the 75 mg you stated taking in the first quote above.

Please clarify.
Helpful - 0
Avatar universal
Hi, this is a follow up on my results. Thank you all so much for your feedback. Not so great news, my new results came in with a ft3 this time. I have raised my Naturethroid dose to 3/4 a grain, these are the results.

TSH : .7 (.3-3)
FT4 : .7 (.8-1.8)
FT3 : 2.6 (2.3-4.2)

Ok. So on a HIGHER dose all three of these levels dropped. Do I need to try adding in Synthroid? My doctor is stumped and recommended taking more Naturethroid. Why are my levels getting worse and not better? Is this just an adjustment period? Please help!
Helpful - 0
393685 tn?1425812522
Not getting the FT3 tests done is kinda the blind leading the blind and I am disappointed in your doctor's followup with you.

Active T3 medication as in NDT allows the cells to absorb it through the blood to deliver active T3 hormone to your entire body to metobolize appropriately. What is s/he basing increases on then if you can't see where the active T3 is doing? Dumb..... dumb.... dumb.

To clarify, FT4 levels is not the level to see HypoT or HyperT (in a sense) but is the "conversion" level of T4 hormone moving into the Active T3 you need to eliminate symptoms of hypothyroidism - and to see if your Active T3 is too high - making you Hyper instead.

Based on your labs, missing the FT3 (ugh!!!) One can only see you are converting the T4 and your pitutiary TSH is responding - but how slow or fast is still a mystery.
Helpful - 0
Avatar universal
It's not unusual for people on NT to have a fairly low FT4.  NT has a high T3 content, compare to what our thyroids produce.  So, FT4 is often low, and FT3 often needs to be on the high side (upper half to upper third of range).

I've no doubt your TSH is suppressed due to the T3 in NT.  As TSH is suppressed, FT4 will go down in response.

I think it's very important for you to test FT3.  FT3 is always important, but once on meds with T3 in them, it becomes imperative.  It's irresponsible of a doctor at that point not to test FT3.  I'd request a retest of FT4 and TSH with FT3 added this time.  If he refuses, your options are to go online and order FT3, FT4 and TSH, try to educate your doctor or find a new doctor.  Self ordered labs are also self pay (about $85 for all three last time I looked).  

Also, please note that your lab's ranges have changed for FT4.  So, in order to compare them, you have to calculate the percentage of range for each.  While your latest labs have the lowest absolute FT4, as a percentage of range, your current FT4 is higher than it was in your original labs.  

Here's how you figure it:

1) subtract the low end of the range from the high end (1.7 - 0.6 = 1.1)

2) subract the low end of the range from your result (0.7 - 0.6 = 0.1)

3) divide result 2 by result 1 and multiply by 100 (0.1 / 1.1 X 100 = 9%)

So, your latest FT4 is 9% of range, and the first was 0% of range, so there is minimal improvement.  Middle labs had the best FT4 of them all.

Have you considered trying a T4-only med?  In your original labs, I see absolutely no evidence of a conversion problem.  Perhaps you just don't need all the T3 in NT.

Helpful - 0
Avatar universal
Thank you both so much for your feedback, it is greatly appreciated. To answer your question, no. I was on no medication during the time my FT3 was 3.0 and my FT4 was a .8. I started on the medication after these levels, to lower my TSH (2.6) and my low FT4. Although now my TSH AND my FT4 are suppressed, and I am lost.
Helpful - 0
1756321 tn?1547095325
"Once on hormone replacement, the TSH remains useful until it goes BELOW 0.4. Then one has optimized thyroid function by the TSH yardstick; it then remains to optimize thyroid function by the yardstick of the accurate measures of the 2 thyroid hormones, the Free T4 and Free T3 levels." Excerpt from Dr Mercola's article - Optimum Diagnosis and Treatment of Hypothyroidism With Free T3 and Free T4 Levels.
Helpful - 0
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