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What does (High) Normal TSH, normal FT4 and High free T3 mean?

My almost 15 year old has a TSH of 3.74 (.5-5), T4 6.5 (4.7-8.6), and Free T3 5.1 (2.9-4.3). His free T4 was normal back in May and TPO is <.5.

What does this mean? He has chronic fatigue but that could be due to other issues, BMI is a bit high and has osteopenia. Our doc is stumped! Can he wait 3+ months to see endo?
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Avatar universal
Has your son hit puberty?  At 15 I would think so. If not, I would suggest you may want to take a look at sex hormones. Particularly testosterone and estrogen. Yes estrogen.

men need estrogen to build bone, as well as testosterone. (so do women but in different ratios, women's loss of what little testosterone they have starting at age about 40 is why osteoporosis is almost exclusively a female issue.  Simple testosterone replacement will solve most brittle and osteo problems in women. But most Dr's won't do it or even know about it.

Testosterone a portion converts to esttogen. So if he is low in testosterone, he could also be low in estrogen, which is why he is not building bone.

How is his muscle tone?  Can he build muscle?  If poor, then that may be another sign of low Testosterone.

Low bone building, and higher Free T3 can cause bone loss.  

High Free T3 also can cause the LOWERING of Cortisol Binding Globulin. But that should result in higher free Cortisol to be available.  So that would not make a lot of sense as Gimel stated above.  Low cortisol can cause FT3 pooling.
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Thanks for your thoughts! He has hit puberty and his testosterone is good. My nurse practitioner who he sees tests and treats women and men em with testosterone so she’s pretty up on it. We haven’t tested his cortisol yet. I’m trying to get his ferritin up then will go back to my NP and have her order all of the suggested labs.
He does build muscle. His mobility is a little limited due to some knee issues (he’s had surgery) and a rare metabolic disease  that causes leg pain. He’s in physical therapy for the knees every week, does exercises at home and walks around at school. That should be enough to not have osteopenia I think. Thanks again!
Avatar universal
Thank you for your suggestions! His ferritin has been low in the past so I check it whenever I can. I don’t eat meat so he doesn’t get it often but I’ll give him some and get the ferritin up and will retest as you suggest. Thanks again! I am reading about the T3 pooling.
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Avatar universal
His B12 is higher than needed.  If supplementing, he can cut back.  Vitamin D should be at least 50, so he is close to that.  The main issue I see is low ferritin.  I know it is within the so-called 'normal" range, but that range is calculated from the database of test results from a lab.  It is not an adjudicated range based on science and expert opinion.  It is just a lab range. that does not indicate adequacy, or optimal levels.  Ferritin should be at least 100.The reason I was especially interested in that is his relatively high Free T3 level, yet he has hypo symptoms.  There is info that claims that low cortisol or low ferritin can cause Free T3 to pool in the blood and not get into cells where it is needed to regulate body functions and prevent hypo symptoms.  I suggest that you get him started on a good OTC iron supplement like VitronC, which contains 65 mg of iron in each tablet.      Other sources are ferrous fumarate, ferrous sulphate, and ferrous bisglycinate.  

I suggest that you focus on getting his ferritin level optimal ,at least 100, and then after 5-6 weeks have him tested for Free T4, Free T3, TG ab.    You might go ahead and make the Endo appt. in case you decide it is needed by that time.  Please keep us tuned in to further results and we can help interpret and advise further.  
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Avatar universal
I wrote a response but just noticed it did not post.  Please give us the actual test results from his B12, Vitamin D and ferritin.  Also what are the H and H results you said were high??
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Sorry for the delay. His Vit D is 46. H and H is hemoglobin and hematocrit. Ferritin was 44 in October. B12 was 1332 in October.
Avatar universal
What are the actual Vitamin D, B12 and ferritin results please?  And what do you mean by his Hand H?
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Avatar universal
Those test results are a bit unusual.  TSH is affected by so many things that it is reliable as an indicator of thyroid status only when it is at extreme levels, which your son's is not.  However the TSH is a bit higher than would be expected, so it was good that the TPO ab test was done.   Hashimoto's Thyroiditis can also show as TG ab so I suggest that test also.   You should make sure they always test him for both Free T3 and Free T4, since those are the active thyroid hormones, different from Total T4 and Total T3.

With Total T4 in the middle of its range, it is puzzling that Free T3 is above range.   This makes me think he should also be tested for cortisol and ferritin (a storage form of iron).  Vitamin D and B12 are also important so I also suggest testing those as well.   Do you think you can get him tested for cortisol, ferritin, Vitamin D, and B12?

Also, symptoms are the most important indicator of thyroid status.  Does he have any of the following symptoms besides fatigue, which is common for teenagers it seems?

Increased sensitivity to cold  (temp. below 98.6 which is considered normal)
Constipation  ( have to use fiber or laxatives)
Dry skin (have to use moisturizer)
Weight gain  
Puffy face    
Muscle weakness
Elevated blood cholesterol level
Muscle aches, tenderness and stiffness
Pain, stiffness or swelling in your joints
Thinning hair
Slowed heart rate
Impaired memory
Enlarged thyroid gland (goiter)
insomnia/sleep apnea
Helpful - 0
Thank you for your reply! He does have some of those other symptoms. 8 of them including fatigue!  I can get those other labs done. His B12, vitD are both ok. His ferritin tends to be a bit low but his H and H are high. Hematologist says that’s ok but our nurse practitioner still thinks it’s weird. We live at 6500 feet for the past 10 years and he was born at 4,500 ft so she’s not buying the altitude excuse.
I’m going to email my NP and ask to to add on those tests. Especially the TG AB and free T4. May have to do the cortisol and ferritin another day. Thanks again!
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