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Doctor insights on: Why Low Tsh And High T4

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My free T4 is high 19.30 pmol/l and my TSH is also high 4.530 mlu/l. What does this mean?

My free T4 is high 19.30 pmol/l and my TSH is also high 4.530 mlu/l. What does this mean?

Few possibilities: These labs seem at odds, with TSH suggesting overactive thyroid and ft4 underactive thyroid. Free T4 tests can be inaccurate in some people who have interfering substances present. Another possibility is a tumor in the pituitary secreting too much TSH resulting in thyroid overactivity, and high thyroid hormone levels. This is quite rare, however. Your doctor can help sort this out. ...Read more

Dr. Quang Nguyen
938 Doctors shared insights

Thyroid Stimulating Hormone (Definition)

A TSH test measures the amount of thyroid stimulating hormone (TSH) in your blood. TSH is produced by the pituitary gland and tells the thyroid gland to make and release the hormones thyroxine ...Read more


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Could a low TSH and high T4 be an indication of iodine deficiency?

Could a low TSH and high T4 be an indication of iodine deficiency?

Iodine deficiency: Iodine is the base for thyroid hormone. Since the T4 is high, it is unlikely that there is an iodine deficiency. It may be possible that you have a thyroid peri oxidase deficiency, which may cause a lack of t3 (liothyronine). You should consult an endocrinologist. ...Read more

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I'm concerned. I have a low TSH and high t4. I'm symptomatic of hyperthyroidism. Can't take ptu (propylthiouracil) or tapazole. What happens now?

I'm concerned. I have a low TSH and high t4. I'm symptomatic of hyperthyroidism. Can't take ptu (propylthiouracil) or tapazole. What happens now?

Diagnosis first: You may or may not have grave's disease. Your doctor needs to determine the cause of your test results before treating test results. Meanwhile, if not contraindicated, a beta blocker could be useful in terms of treating hyperthyroid symptoms. Causes of your hyperthyroidism also include: hashimoto's, subacute thyroiditis, and toxic thyroid nodule. ...Read more

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What is meant by low TSH high free t4?

What is meant by low TSH high free t4?

Hyperthyroidism: A low TSH and high T4 is an indication of over-active thyroid (hyperthyroidism). This should be evaluated further for any potential cause and discuss treatment options with your physician. Referral to an endocrinologist may be necessary. ...Read more

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Low TSH high free t4? What is the cause?

Low TSH high free t4? What is the cause?

Hyperthyroidism: High ft4 and low TSH are a combination usually indicating an over active thyroid. It doesn't explain the cause which will require further testing to figure out. ...Read more

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Very low TSH with high normal free T4. Twitching. Changed dose. How long til levels normal out? Still twitching 2 weeks later. Had basic neuro exam.

Very low TSH with high normal free T4. Twitching. Changed dose. How long til levels normal out? Still twitching 2 weeks later. Had basic neuro exam.

What did you: Change the dose of? If it's thyroid replacement, it can take weeks for the level to normalize, asumming you're now on the correct dose. If it's an ANTI-thyroid drug, it can takes months to work as it only inhibits the formation of NEW thyroid hormone, not the hormone that's already been manufactured. ...Read more

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Does low TSH mean I have a problem with my pituitary gland? Hypopituitarism? My free T3 (liothyronine) and T4 are high normal???

Does low TSH mean I have a problem with my pituitary gland? Hypopituitarism? My free T3 (liothyronine) and T4 are high normal???

Low TSH: May reflect Hypopituitary condition if FT4 and FT3 are low also. However if both are high that will indicate Hyperthyroidism. Discuss with your doctor about other modifers like acute illness or medication effects or pregnancy on your thyroid panel result ...Read more

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My 10yr old daughter had lab work completed and the results show a high esr, low tsh, and normal t3/t4. What are possible diagnosis?

My 10yr old daughter had lab work completed and the results show a high esr, low tsh, and normal t3/t4. What are possible diagnosis?

Possibly thyroiditis: The information is incomplete, but subacute thyroiditis (sat), an inflammation of the thyroid gland can cause hyperthyroidism and high esr. People with sat have severe neck pain. With no pain sat is unlikely. A high ESR is found in many non-thyroid conditions: one can have mild hyperthyroidism and another cause for a high esr. Some people with non-thyroid illness have low TSH without being hyper. ...Read more

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Had total thyroidectomy 10 years ago. Currently 8 weeks pregnant, taking synthroid (thyroxine) 125mcg. Very low TSH 0.01 and high free T4 at 26 (normal 12-22).?

Way off: That dose of thyroid needs to be reduced ASAP. Please consult with your doctor right away. I'm guessing they're doing that already if they received those test results. ...Read more

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Normal range T3/T4 but extremely low TSH (high sensitivity). Slightly low before pregnancy and now extremely low 11 weeks. Endocrine Dr not concerned?

Normal range T3/T4 but extremely low TSH (high sensitivity). Slightly low before pregnancy and now extremely low 11 weeks. Endocrine Dr not concerned?

Low TSH: Agree not to worry, your hormone levels are fine and the TSH being slightly is because you are pregnant, just like other things that change with pregnancy.
Don't worry. ...Read more

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Could a low TSH (.28) & normal T3 (liothyronine) & T4 levels mean a Pituitary issue? Or is that more typical of hypothyroidism? Would high Chloride (111) effect it?

Could a low TSH (.28) & normal T3 (liothyronine) & T4 levels mean a Pituitary issue? Or is that more typical of hypothyroidism? Would high Chloride (111) effect it?

Means pituitary is: A TSH of 0.28 with normal free T4 and free T3 (liothyronine) likely means the pituitary is working properly. A TSH of 0.1-0.4 is lower than the reference range, which means about 2.5% of normal people have a TSH or 0.1-0.4. Thus, one hopes she is normal. Her endocrinologist can follow and recheck her levels in 4-6 weeks to confirm that her levels are stable (TSH not dropping lower; T4 or T3 (liothyronine) not above normal). ...Read more

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What does it mean when you have a low TSH but you also have a low t4?

Thyroid labs: Hi. See an endocrinologist. Make sure it's a free T4 (not a TOTAL T4). If you have low TSH and a low free T4, that's compatible with pituitary disease causing hypothyroidism (so called "secondary hypothyroidism"). IF you have that (not saying you do), you need to be checked for pituitary problems and other pituitary deficiencies (adrenal, most promptly); If u have secondary hypothy, CHECK ADRENALS ...Read more

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What could be the reason for a low T4 and low TSH on the bloodwork?

How low?: If these were taken during a time that you were emotionally distraught, and they are not strikingly removed from the reference range (which is set so that several percent of healthies fall outside), your physician will repeat them when your life gets better. If way-low, pituitary disease is a concern. ...Read more

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My 19 year old son has labs showing low TSH but normal free t4. What could that indicate?

My 19 year old son has labs showing low TSH but normal free t4. What could that indicate?

Depends: On the level of tsh. If TSH level remains in the range 0.2-0.6, he is at very low risk of developing hyperthyroidism. Retesting is not recommended. ...Read more

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What does low TSH 0.2 with normal free T4 mean? What is its treatment and does it need to be taken all life long?

Likely normal: Your TSH may be slightly low and may be normal for you. Do you have any symptoms? It is generally not a good idea to treat lab values. All lab results need to be interpreted in the clinical context and the doctor who ordered the tests is usually in the best position to do that. It is likely that you need no treatment, however, it would be prudent to follow your doctor's advice for follow up tests. ...Read more

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What causes low TSH, low T4 and low T3 (liothyronine)?

See below: All laboratory results need to be interpreted in the clinical context and the doctor who ordered the tests is usually in the best position to do that. Having said that, it would have helped to know the actual values. Even though all these parameters may be low, these may yet be in the normal range. ...Read more

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What does low T4 and low TSH signify on a thyroid test?

What does low T4 and low TSH signify on a thyroid test?

Need more info: All laboratory results need to be interpreted in the clinical context and the doctor who ordered the tests is usually in the best position to do that. Having said that, it would have helped to have the actual values rather than your interpretation of the results.
For good health - Have a diet rich in fresh vegetables, fruits, whole grains, milk and milk products, nuts, beans, legumes, lentils and small amounts of lean meats. Avoid saturated fats. Drink enough water daily, so that your urine is mostly colorless. Exercise at least 150 minutes/week and increase the intensity of exercise gradually. Do not use tobacco, alcohol, weed or street drugs in any form.
Practice safe sex, if you have sex. ...Read more

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What does it mean if my T3 (liothyronine) is low? TSH and T4 totals are normal.

Nothing: First how low is low.

generally T3 (liothyronine) alone does not mean anything. Specially with normal TSH, and T4

that mean your thyroid is functioning well.

check with your doctor. ...Read more

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Could a low TSH but normal Free T4 mean a Pituitary problem? Or would that be more indicative of the start of Hypothyroidism?

Sounds normal: Your description is consistent with normal thyroid function, but if you are concerned, you could provide exact numbers for us to review. ...Read more

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I am diagnosed with low TSH and normal T3 and T4 level...What does it mean? Please suggest me treatment...

T3 and T4: A low TSH should not affect your thyroid glands!
If you are having a problem please see an Endocrinologist. Should not be necessary. ...Read more

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Can Lamotrigine (Lamictal) affect TSH levels? Also, what do low TSH mean (if T3 (liothyronine) and T4 are normal)?

Not alot: Thyroid interaction is not common with Lamictal, however as with all medications for each individual that can be a possibility. As to your low TSH that is usually a resonse to elevated T3, (liothyronine) T4. Remember that there can be variations in your thyroid measurements from one time to another. How do you feel. Do you have thyoid symptoms: cold, tired, fatigued, skin or nail changes? ...Read more

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I have hypothyrodism. Taking eltroxin 100. what does it mean to have T3 (liothyronine) and T4 in normal range while having a low TSH? 0.22

Good control!: Those figures sound swell. The normal range for both circulating thyroid hormones plus a low TSH (= Thyroid stimulating hormone) from your pituitary gland the "controller" at the base of your brain means the medication is being given in the correct dose!! Its good news! ...Read more

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Total thyroidectomy 8 yrs ago. Nowadays I am gaining weight. Recent labs low TSH 0.362 T3 =90, T4=6.9 Synthroid decreased 125 mcg to 112 mcg.?

Total thyroidectomy 8 yrs ago. Nowadays I am gaining weight. Recent labs low TSH 0.362 T3 =90, T4=6.9 Synthroid decreased 125 mcg to 112 mcg.?

Aging: All laboratory results need to be interpreted in the clinical context and the doctor who ordered the tests is usually in the best position to do that. Having said that, The weight gain may be due to general slowing of metabolism with aging. Your thyroid function test results seem okay. You may need to reduce your intake of food and exercise more. ...Read more

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I have hypothyroid from 6 months and recently when tested got t3-1.25, t4-8.54, tsh-0.018. Is it dangerous to hav such low TSH and do it affect fertilit?

I have hypothyroid from 6 months and recently when tested got t3-1.25, t4-8.54, tsh-0.018. Is it dangerous to hav such low TSH and do it affect fertilit?

It depends: I assume you are taking thyroid hormone for your diagnosis of hypothyroidism. The low TSH tells us that you are taking too much thyroid hormone. However, the normal T4 and T3 (liothyronine) levels tell us that you need only a slightly lower dose. Any time the thyroid level is off, it can affect fertility, so you want to have it normal. ...Read more

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Normal T3 (3.53) and T4 (1.42), very low TSH (0.02), thyrogobulin is 69, thyroid uptake imagining "significantly abnormal and below normal range"...

Normal T3 (3.53) and T4 (1.42), very low TSH (0.02), thyrogobulin is 69, thyroid uptake imagining "significantly abnormal and below normal range"...

Unusual combination: This is a very unusual combination of results +scan. The most likely cause (if you are not taking excess thyroid hormone and have appropriate Iodine levels in your blood) is thyroiditis, Which type would need antibody assessment and exam of the gland. ...Read more

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I had a total thyroidectomy due to cancer. My lab shows low tsh but t4 and t3 (liothyronine) levels are normal indicating correct dosage why would my tsh be low?

TSH: TSH may be low simply because your thyroid meds are doing enough to keep the TSH at a low level.
If you are feeling OK just relax and enjoy life! ...Read more

Dr. David Sneid
1,420 Doctors shared insights

Thyroxine (Definition)

Thyroxine is a thyroid agent. ...Read more