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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.

Dr. Quang Nguyen
933 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.

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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.

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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.

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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.

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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.

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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

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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.

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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.

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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.

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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).

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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

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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.

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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.

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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.

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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.

Dr. David Sneid
1,413 Doctors shared insights

Thyroxine (Definition)

Thyroxine is a thyroid agent. ...Read more