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normal TSH, low free T4
Below are my lab levels. I am on lithium carbonate. Please explain!
TSH 2.900 uIU/mL (0.450-4.500)
Thyroxine (T4) 3.9 LOW ug/dL (4.5-12.0)
T3 Uptake 27 % (24-39)
Free Thyroxine Index 1.1 LOW (1.2-4.9 )
T4,Free(Direct) 0.73 LOW ng/dL (0.82-1.77)
Triiodothyronine,Free,Serum 2.7 pg/mL (2.0-4.4)
Do you treat the T4 even if the TSH is normal? I have experienced 10lb weight gain in the past year in spite of eating better but perhaps this is a reflection of my age (35). No other symptoms really to report.
Thank you so much in advance.
TSH 2.900 uIU/mL (0.450-4.500)
Thyroxine (T4) 3.9 LOW ug/dL (4.5-12.0)
T3 Uptake 27 % (24-39)
Free Thyroxine Index 1.1 LOW (1.2-4.9 )
T4,Free(Direct) 0.73 LOW ng/dL (0.82-1.77)
Triiodothyronine,Free,Serum 2.7 pg/mL (2.0-4.4)
Do you treat the T4 even if the TSH is normal? I have experienced 10lb weight gain in the past year in spite of eating better but perhaps this is a reflection of my age (35). No other symptoms really to report.
Thank you so much in advance.
Unfortunately, there isn't a dose range. If there were, we'd all have an easier time finding our best dosage. It depends on so many things...how much thyroid function you have remaining, how you react to meds in general, where your personal comfort level is, even how much you weigh, etc.
It takes 4-6 weeks for a dose to reach its full potential in your blood. So, I wouldn't expect you to be feeling much of anything yet.
It takes 4-6 weeks for a dose to reach its full potential in your blood. So, I wouldn't expect you to be feeling much of anything yet.
25 mcg is a very small dose. It's really not going to do much, but it's better to start out low and increase slowly. Otherwise, you can get hyper-like symptoms, which are less than pleasant. How long have you been on it?
Thank you so much! I really appreciate your input once again:) Will keep all these factors in mind. I'm not sure what final dose to expect as I feel exactly the same on 25mcg.
How often labs should be done depends on what stage you are in your treatment. In the beginning, when meds are actively being adjusted, you really should have blood work 4-5 weeks after the adjustment to see how the new dose has affected your labs. Once on a stable dose, you can stretch that out considerably. I'm now down to once a year. I also think it's a very good idea to have a set of labs drawn when you are feeling really good. If you start feeling not well again, that healthy set can guide your meds adjustment.
Both FT3 and FT4 should go up as a result of the meds. Practically speaking, FT3 can be slow in tracking FT4 up. However, in my opinion, you can't draw too many conclusions about conversion until FT4 is about 50% of range. Of course, if your symptoms resolve in the process, you have arrived.
Once on meds, many TSH drops, sometimes to close to zero. This happens more frequently when adding T3, but it's not unheard of when starting T4 either. FT3 and FT4 are much more reliable indicators.
Both FT3 and FT4 should go up as a result of the meds. Practically speaking, FT3 can be slow in tracking FT4 up. However, in my opinion, you can't draw too many conclusions about conversion until FT4 is about 50% of range. Of course, if your symptoms resolve in the process, you have arrived.
Once on meds, many TSH drops, sometimes to close to zero. This happens more frequently when adding T3, but it's not unheard of when starting T4 either. FT3 and FT4 are much more reliable indicators.
I don't think he's doing lab work in 2 weeks. He's more of the alternative type who looks at symptoms. How often should lab work be done? Would the success of the drug be reflected in the increase in free T4? Should the TSH which was normal to begin with just be ignored even if it drops low? Thank you!!
I'm so glad to hear you're starting meds! I agree that you could have secondary hypothyroidism, which is actually a pituitary dysfunction.
You're starting out on a nice low dose, so there shouldn't be any big surprises. You'll probably have several adjustments before you find the right dose. Are you having blood drawn in two weeks or just re-evaluating meds?
You're starting out on a nice low dose, so there shouldn't be any big surprises. You'll probably have several adjustments before you find the right dose. Are you having blood drawn in two weeks or just re-evaluating meds?
Goolarra,
I can't thank you enough for your help. I finally saw another doc today who felt the labs warranted synthroid. I will start tomorrow at 25mcg and follow up in 2 weeks. He thought that there was a pituitary issue of sorts that is resulting in a high tsh but low free T4. Stay tuned. What should i keep in mind/expect, etc.? thank you again!!
I can't thank you enough for your help. I finally saw another doc today who felt the labs warranted synthroid. I will start tomorrow at 25mcg and follow up in 2 weeks. He thought that there was a pituitary issue of sorts that is resulting in a high tsh but low free T4. Stay tuned. What should i keep in mind/expect, etc.? thank you again!!
Hi Sarah,
Have you discussed this with the physician who is prescribing the Lithium? Or considering switching to another mood stabilizer?? It's not uncommon today for psychiatrists to prescribe T3 (Cytomel) as a boost to an SSRI.
Take care,
Sarah
Have you discussed this with the physician who is prescribing the Lithium? Or considering switching to another mood stabilizer?? It's not uncommon today for psychiatrists to prescribe T3 (Cytomel) as a boost to an SSRI.
Take care,
Sarah
Thanks Sarah! I was hoping that i could get synthroid to counteract the lithium impact but it seems rather difficult to be treated without an abnormal Tsh. (my free T4 is low). I really appreciate your input.
Hi Sarah,
There have been many studies that have shown that lithium inhibits thyroid function. In fact, it has been documented that many patients on long-term lithium will develop hypothyroidism. You might want to consider changing from lithium to another medication that doesn't negatively impact the thyroid.
Sarah
There have been many studies that have shown that lithium inhibits thyroid function. In fact, it has been documented that many patients on long-term lithium will develop hypothyroidism. You might want to consider changing from lithium to another medication that doesn't negatively impact the thyroid.
Sarah
She also didn't test FT3, which is not good.
In addition to Hashi's, there are several "temporary" or self-resolving kinds of thyroiditis. One of those, deQuervain's thyroiditis, is characterized by elevated TG. She probably tested TG to rule that out. If she hasn't tested TGab, she should. Some of us are TPOab positive, some TGab positive and some both.
In addition to Hashi's, there are several "temporary" or self-resolving kinds of thyroiditis. One of those, deQuervain's thyroiditis, is characterized by elevated TG. She probably tested TG to rule that out. If she hasn't tested TGab, she should. Some of us are TPOab positive, some TGab positive and some both.
Yes, having trouble with normal TSH; that is exactly the problem. Asked doctor a series of questions and she basically told me that she'd just like to "wait and watch." I will still pursue an Endo. I'm tired and still up 15 pounds, etc. Thank you for being so caring and informative. It really means a lot as this has been quite frustrating. What is the value of testing Thyroglobulin? Shouldn't she have tested more antibodies instead?
It definitely warrants treatment. FT4 is still below range, which indicates hypo. The problem is your TSH. Unfortunately, it's flat out "normal", and many doctors will look at that and tell you that you're just fine. So, finding an enlightened doctor is key.
How have you been feeling lately?
How have you been feeling lately?
Hello! So more testing was done.
The most recent values:
Free T4 - 0.6 Low (0.7-1.5)
TSH 3rd Gen - 1.68 (0.4 -4)
Thyroglobulin - 6.93 (1.6 - 50)
Thyroid Peroxidase Antibody 0.5 (0.0 -8.9)
Thoughts?! Does this warrant treatment? Trying to be patient.....
Thank you again!
The most recent values:
Free T4 - 0.6 Low (0.7-1.5)
TSH 3rd Gen - 1.68 (0.4 -4)
Thyroglobulin - 6.93 (1.6 - 50)
Thyroid Peroxidase Antibody 0.5 (0.0 -8.9)
Thoughts?! Does this warrant treatment? Trying to be patient.....
Thank you again!
I'd follow up on the D. For proper synthesis of thyroid hormones, D has to be well up into the range. Also, D is necessary for thyroid hormones to get into cells. We see some serious deficiencies these days, and doctors will put patients on as much as 50,000 IU per week until levels rise then back off to a maintenance dose. Iron/ferritin also figures into thyroid hormone synthesis and transport into cells.
I think it would be worth seeing an endo. Do you plan to interview them before making an appointment?
I think it would be worth seeing an endo. Do you plan to interview them before making an appointment?
i haven't followed up with the vitamin D. I assume it's being absorbed? Will add the ultrasound to the list:) Thank you.
How much vitamin D are you taking, and have you followed up to see if your level is rising?
Thyroid nodules are characteristic of Hashi's. If you have nodules it would bolster the TGab result.
Thyroid nodules are characteristic of Hashi's. If you have nodules it would bolster the TGab result.
Yes, I was tested a few years ago and the vitamin D was low. I take it daily. What is the value of an ultrasound? Thank you!! Will book endo appointment to settle the low T4 hopefully.....
I wouldn't say it's of no concern, but I would say it's a distinctly "borderline" result. Two reasons for that: 1) By far, most of us who have Hashi's are TPOab positive. Some of us are both, but TPOab is the big one. A few are only TGab positive. 2) TGab can be somewhat elevated with other autoimmune diseases (you never see the term "somewhat" defined). It's not unusual for antibody counts to be in the high hundreds or even thousands on diagnosis of Hashi's. So, this could be the start of something, though not necessarily thyroid disease, and it could be irrelevant.
Have you had an ultrasound?
The hot flashes: The whole endocrine system, of which both thyroid and reproductive hormones are a part, is interrelated. If hormones in one part are off, it throws the whole thing off. But, it becomes a chicken and egg question. Is your thyroid off because your reproductive hormones are off or vice versa? Estrogen is a thyroid hormone antagonist. So, if your reproductive hormones are bouncing around, as they do during peri-menopause, that could be contributing to your thyroid issue.
Have you ever had vitamin D tested?
Have you had an ultrasound?
The hot flashes: The whole endocrine system, of which both thyroid and reproductive hormones are a part, is interrelated. If hormones in one part are off, it throws the whole thing off. But, it becomes a chicken and egg question. Is your thyroid off because your reproductive hormones are off or vice versa? Estrogen is a thyroid hormone antagonist. So, if your reproductive hormones are bouncing around, as they do during peri-menopause, that could be contributing to your thyroid issue.
Have you ever had vitamin D tested?
One other question if you don't mind - I'm in my 30s but I'm having hot flashes. Could this be thyroid related?
Ok so here are the latest lab results. Thoughts?
Thyroglobulin antibody = 1.2 HIGH (range 0.0 -0.9)
TPO antibody = 7 NORMAL (range 0-34)
Is this of no concern because they Thyroglobulin antibody is just a little high? Or is this diagnostically significant in light of the low free T4. Please explain. Thank you so much as always.
Thyroglobulin antibody = 1.2 HIGH (range 0.0 -0.9)
TPO antibody = 7 NORMAL (range 0-34)
Is this of no concern because they Thyroglobulin antibody is just a little high? Or is this diagnostically significant in light of the low free T4. Please explain. Thank you so much as always.
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Total T4 and T3U are considered obsolete test of little value.
Your FT4 is below range, which means your thyroid isn't making adequate amounts. FT3 is in the lower third of the range, and it belongs in the upper half.
TSH is a pituitary hormone and as such is affected by many factors other than thyroid hormone levels. So, it's the least important of the thyroid tests, although doctors have been taught that it's the gold standard in thyroid testing. FT3 correlates best with symptom, FT4 falls behind it, and TSH does not correlate at all. So, the most alarming number there is your FT4, which is below range. It can be difficult to find a doctor who will treat FT4 and ignore TSH.
It's the lithium:
http://www.ncbi.nlm.nih.gov/pubmed/9827658
How long have you been on lithium? The study suggests that the hypothalamus/pituitary/thyroid axis might be "reset" when starting lithium.