Avatar universal

Help with thyroid test results.

Help with lab results.  Taking NP Thyroid.  Free T3 is 4.3.  TSH is 23.  T4 is 5.7.  How can Free T3 be high and TSH bee high?
8 Responses
Sort by: Helpful Oldest Newest
Avatar universal
Here is my two-bits worth, some of which other people have already said. Your results on 125 Levo were fairly typical - that is, your FT4 is highish, your FT3 quite low, and consequently you suffer from fatigue. It is too bad you had to put up with it since 1998.

On 75 mg NP Thyroid, which contains 48 mcg T4 plus 11 mcg T3: this dose is only half of what is usually required. So it is no wonder that your Total T4 is very low and your TSH is very high - which are indicating that you are hypothyroid.  Your high free T3 can be explained, because your T3 spikes higher for several hours following taking the pill.

Your doctor's new dose of 60 mg NP Thyroid plus 15 Levo is a very modest change to a total of 53 mcg T4 plus 9 mcg T3, so I predict that you will feel pretty much the same and next labs will have high TSH and both FT4 and FT3 will be low if you do the labs before taking your morning pill.

You said the doctor said the lab results were odd. Therefore he should have ordered a repeat of the tests. I think he is misinterpreting the test results and he should have increased you to 120 NP Thyroid which is a much more typical low end amount of NP, but it probably would be difficult for you to convince him of that.

It appears that you waited about 4 months (March to July) between getting labs. It takes 4 to 5 weeks to reach equilibrium after making a thyroid dose change. Perhaps you could point out to your doctor that your labs are obviously not normal and you are together trying to determine what the proper dose is and you are tired of feeling crappy and so why can't you get new labs tests at 5 weeks rather than several months?? Then you could get to the proper dose faster. Good luck.
Helpful - 0
Thank you so much for all your responses.  It's very good information.
Avatar universal
Sorry for the typo in paragraph 3.  It should be "One grain of NDT (60) mg is only equivalent to about 65 mcg of T4."
Helpful - 0
Avatar universal
Based on the range and the description of T4, that test is for Total T4, which is not nearly as important as Free T4.  

In March your FT4 was high at 1.8, which is 91% of its range, and higher than needed.     At that time your FT3 was at rock bottom of the range, at 2.3, which is way too low.  A person's thyroid status is dependent on the amount of TISSUE T3 EFFECT.   T4 is just a prohormone that has to be converted to T3 to be utilized by the body.   Your high FT4 and low FT3 show  poor conversion of T4 to T3.  At that time your TSH was 2.4, which is not unusual with those FT4 and FT3 levels.  

Since you were having severe fatigue, the doctor apparently decided to switch you to NDT to try and raise your FT3 level.  The doctor should also have tested for ferritin, since it is very important in the conversion of T4 to T3.   Also the switch to 75 mg of NDT was actually a reduction in med.  One grain of NDT (60) mg is only equivalent to about 6f5 mcg of T4.   So your 75 mg of NDT is equivalent to about 81 mcg of T4. So you went from 125 mcg of T4 to an equivalent of only about 81 mcg.  

Now you were changed from 75 mg of NDT to 60 mg plus 15 mcg of Levo (T4), apparently due to your FT3 of 4.3.  Unfortunately we cannot be sure of what your FT4 and FT3 levels really are since you took the med before the blood draw for those tests, which can cause false high readings, especially for FT3.  Also, in view of your really low Total T4, I am no longer sure of what the TSH result of    23.2 indicates.    You will know more after your next round of tests, so I would not bother asking about a potential pituitary  issue until after those results.  

Where to go from here?   First thing is to always delay your morning med dosage until after the blood draw for thyroid tests.   This is even recommended by the AACE/ATA Guidelines for hypothyroidism.  

Next thing is that you should always make sure they test for both Free T4 and Free T3 (not Total T4 or Total T3) every time you go in for tests.   Doctors always test for TSH.  In addition, hypothyroid patients are frequently deficient in Vitamin D, B12 and ferritin, so those should also be tested.   D should be at least 50 ng/mL, B12 in the upper part of its range, and ferritin should be at least 100.  It is also a good idea to test for cortisol, since it affects thyroid.  

Also, I thought of some more info you might find useful for your appointment.  First is to point out  that the thyroid gland of a healthy person, produces approximately 94-110  micrograms of T4 daily along with 10-22 micrograms of T3.   The AACE/ATA Guidelines for Hypothyroidism states that T3 is 3 times as potent as T4.  Taking into account the low and high amounts included in the ranges for the T4 and T3, and converting those values  to equivalent T4 in order to compare with desiccated med containing both T4 and T3, the daily output of thyroid hormone would be equivalent to somewhere between 124 and 176 micrograms of T4 (94 + 3 times 10, and 110 + 3 times 22).

A grain of NDT med (60 or 65 milligrams) contains 38 micrograms of T4 and 9 micrograms of T3.  For comparison, converting that to the equivalent amount of T4 would give a value of 65 milligrams of T4 (38 + 3 times 9).   After RAI and supposedly no thyroid gland output, a full daily replacement amount of thyroid med is required,  So a normal thyroid gland output equivalent to somewhere between 124 and 176  micrograms of T4, approximately equal to 2 to 3 grains of NDT (120 to 180 milligrams), would be required for a full daily replacement amount.  Assuming that 80% of thyroid med is absorbed into the blood, which may be somewhat high,  a full daily replacement dose of desiccated thyroid med would thus need to be at least somewhere between 2.5 and 3.75 grains (150 to 225) milligrams.  So you can understand why your dose of of 60 NP Thyroid plus 15 mcg of Levothyroxine is way too low, and will result in hypo symptoms    Thyroid med dosage should be adequate to relieve hypo symptoms.  The above is only  a general approach to determining how much replacement thyroid med may be needed, but it  shows why your med dosage is too low, since it is not even providing a full daily replacement amount.  

A good thyroid doctor will do the listed tests,  and treat clinically, by adjusting  medication dosage  to raise your FT4 and FT3 levels as needed to relieve symptoms, without being influenced by resultant TSH levels.   Symptom relief should be all important, not just lab test results.    Also, med dosage should never be determined based on TSH levels.   I'll explain more about that if interested.
Helpful - 0
Avatar universal
I think Gimel was asking about were yout taking the NP thyroid when you had your labs done. he was asking if you took your thyroid medicine on the same morning as your blood was drawn before the blood was drawn for the testing.  That would result in a false high Free T3 result and possibly Free T4 result as well.

Also are you sure the latest T4 lab result you had of 5.7 ( 4.5 - 10.5).  Or is that "total T4" rather than Free T4?  That range is odd for Free T4 unless the units are different.  More common free T4 range is somthing similar to (0.8 - 1.8).

TSH is wierd result.  and clearly you cannot go by TSH to guide your dosage changes to relieve symptoms.  However, as Gimel pointed out. There could be somethign else going on with the pituitary that you may want to check out.

Have you had your prolactin checked.  I think, sometimes with an adenoma prolactin will be high. But I could be wrong about that.
Helpful - 0
yes I took it that morning befor the labs.  If that me be the problem, then I will take it after the blood test next time....
the t4 test did not say free t4.  It just says t4.
Avatar universal
I was hoping to get a full response to my questions before further discussion: however, flyingfool is correct  that something doesn't add up with you having had RAI, but high TSH with those thyroid hormone levels, while only taking 75 mg of NDT.    I am suspicious that the RAI did not kill off all your thyroid tissue and one possibility that came to mind that could cause your situation is perhaps a TSH secreting pituitary adenoma  causing the high TSH which is stimulating the remaining tissue to produce  T4 and T3.  In combination with your med dosage that is apparently more T4 and T3 than you need.    This is something you should pursue with your doctor.  

Also please tell us about any symptoms you have.  Also please post the reference ranges shown on the lab report for those test results.   Also, were you taking 75 mg of NP Thyroid when those tests were done?
Helpful - 0
Yes, taking 75mg of Np Thyroid when test was done.  Test Ranges:
done in March 2019 on 125 mcg levothyroxin:
Free T3  at 2.3 lab ranges 2.2 to 4.2. Free T4 at 1.8 lab ranges .8 to 1.90
TSH at 2.4  lab ranges .4 to 4.1.   Feeling extreme fatigue even though un lab ranges.   Changed to 75 NP Thyroid.  Test in July 2019.  Free T3 4.3 Lab ranges 2.2 to 4.2.  T4:  5.7. Lab ranges 4.5 to 10.5.  TSH at 23.270  lab ranges. .4 to 4.1.     Feel better with the higher free t3 than with prior test in march.  Just think the TSH looks wierd.  My cholesterol is higher this test as well.  Went from 212 to 256.  Dr said the results are strange.  He is changing me again to 60 Np Thyroid plus 15 levothyroxin.  Will have another test in a couple of months.
Avatar universal
something doesn't seem right here.

As stated we really need to see the reference ranges with those tests. However, if the ranges are what are typically seen.  You are WELL up if not over the top of the ranges of both FT4 and FT3.

Also if the RAI was successful, that would mean your thyroid is dead.  However the 75 mg NP thyroid is not a very high, dose, yet your FT4 and FT3 are high.

I don't know if this is possible, but it almost seems "as if", your thyroid is still producing thyroid hormone, and the NP thyroid is adding to it.  Normally you would see a suppressed TSH, but because it is not suppressed due to the medication, the thyroid gland is still getting the TSH signal to produce.  So your pituitary is not "reading" the situation correctly.  And it still thinks (like in graves) that you are low on thyroid and needs to tell your thyroid to produce.  This odd theory would seem to explain why the TSH is high, and why the FT4 and FT3 levels are higher than what one would normally expect for a smaller to moderate dosage of NP thyroid.

Just a wild guess on my part.
Helpful - 0
Avatar universal
Lab test results and associated reference ranges vary from one lab to another, so to assess your test results, we need to know the reference ranges shown on the lab report for those results.   Also pllease review this list of symptoms typical of hypothyroidism and tell us about any that you have.  

Aches and pains
Cold hands and fee
tDecreased sweating
Need excessive sleep
Weight gain
Losing scalp hair
Dry skin (need to use skin moisturizer)
Mental slowness
Helpful - 0
Avatar universal
Could you please give us some more background info.  When you were diagnosed as hypothyroid, was it because of a high TSH?  If so, were you also tested for the possibility of Hashimoto's Thyroiditis?  Those tests would be Thyroid Peroxidase antibodies (TPO ab) and  Thyroglobulin antibodies (TG ab).   What symptoms, if any, did you have at that time?   If tested for Free T4 and Free T3 at that time please post results and reference ranges shown on the lab report.  

How much NP Thyroid are you taking daily?  

Please post the reference ranges shown on the lab report for those test results  you listed.   Also  tell us about any symptoms you are having currently.  
Helpful - 0
I had Graves Disease diagnosed and had RAI back in 1998.  No other tests were done this last time.  I am not sure if I was tested for Hashimotos but suspect I have it.  I was on Nature throid at one time and my THS did not show up (below 0) so I don't know why it is so high now.  I currently take 75mg of Np Thyroid.  I suspect the dose is not high enough, but my free t3 is close to normal..  My symptom was extreme fatigue before I was switched from 125 mcg levothyroxon to 75mg of Np Thyroid. I feel a little better now, but concerned my THS is 23.  Maybe it doesn't matter.
Have an Answer?

You are reading content posted in the Thyroid Disorders Community

Top Thyroid Answerers
649848 tn?1534633700
Avatar universal
1756321 tn?1547095325
Queensland, Australia
Learn About Top Answerers
Didn't find the answer you were looking for?
Ask a question
Popular Resources
We tapped the CDC for information on what you need to know about radiation exposure
Endocrinologist Mark Lupo, MD, answers 10 questions about thyroid disorders and how to treat them
A list of national and international resources and hotlines to help connect you to needed health and medical services.
Herpes sores blister, then burst, scab and heal.
Herpes spreads by oral, vaginal and anal sex.
STIs are the most common cause of genital sores.